CN108583561B

CN108583561B - Method and system for improving hybrid vehicle transmission shifting

Info

Publication number: CN108583561B
Application number: CN201810174484.XA
Authority: CN
Inventors: 詹森·迈尔; 杰弗里·艾伦·多林; 王小勇; 马修·约翰·谢尔顿; 克里斯·约翰·特斯拉科; 肯尼斯·詹姆斯·米勒
Original assignee: Ford Global Technologies LLC
Current assignee: Ford Global Technologies LLC
Priority date: 2017-03-09
Filing date: 2018-03-02
Publication date: 2023-03-10
Anticipated expiration: 2038-03-02
Also published as: US10919518B2; US20180257635A1; DE102018104821A1; CN108583561A

Abstract

The present disclosure provides a method and system for operating a powertrain of a hybrid vehicle that includes the described internal combustion engine, rear wheel drive motor, integrated starter/generator, and transmission. In one example, inertia torque compensation is provided to counteract inertia torque during a power-on upshift.

Description

Method and system for improving hybrid vehicle transmission shifting

Technical Field

The present invention generally relates to a method and system for controlling a powertrain of a hybrid vehicle. The method and system may be particularly useful for hybrid vehicles that include an electric machine downstream of a transmission in a driveline.

Background

Hybrid vehicles may be equipped with one or more electric machines. The electric machine may be deployed in a hybrid vehicle in several different ways. For example, the electric machine may be selectively connected to the engine in different ways, including at a location upstream of the transmission, directly through the gearbox, not connected to the engine, and at a location downstream of the transmission. Locating the electric machine downstream of the transmission has some advantages, such as improving driveline efficiency by allowing the electric machine to propel the hybrid vehicle without having to rotate all of the rotating mass in the transmission. However, locating the electric machine downstream of the transmission also presents some challenges. Specifically, locating the electric machine downstream of the transmission can make smooth shifting more challenging because engine torque is not directly absorbed by the electric machine. Furthermore, providing smooth transmission shifts may be even more difficult as the electric machine may provide torque to or absorb torque from the driveline. Accordingly, it is desirable to provide the benefit of locating the electric machine downstream of the transmission in the direction of positive driveline torque flow, while providing smooth transmission shifting.

Disclosure of Invention

The inventors herein have recognized the above-mentioned problems and have developed a method of operating a powertrain comprising: the transmission input torque is reduced by the controller during a power-on upshift to a transmission transient upper threshold torque responsive to the recorded transmission torque ratio, the transmission torque ratio under the new gear, the transmission inertia, and the duration of the desired transmission upshift.

According to the present invention, there is provided a method of operating a powertrain, the method comprising:

the transmission input torque is reduced by the controller during a power-on upshift to a transmission transient upper threshold torque responsive to the recorded transmission torque ratio, the transmission torque ratio under the new gear, the transmission inertia, and the duration of the desired transmission upshift.

According to one embodiment of the invention, the transmission torque ratio recorded in the method is determined from a transmission input speed and a transmission output speed, and the method further comprises:

the transmission input torque is reduced to less than the transmission hardware upper threshold.

According to one embodiment of the invention, the transmission torque ratio recorded in the method is determined by the clutch capacity of the oncoming clutch and the torque ratio of the transmission when the transmission engages the new gear.

According to one embodiment of the invention, the new gear in the method is a gear engaged immediately after the power-on upshift is completed.

According to one embodiment of the invention, the method wherein the torque of the engine is adjusted to a value of the instantaneous upper threshold of the transmission.

According to one embodiment of the invention, the method wherein reducing the transmission input torque comprises reducing the torque of an electric machine of the rear wheel drive or of a motor or electric machine comprising a separate drive shaft disposed directly downstream of the transmission output.

According to one embodiment of the invention, the method wherein reducing the transmission input torque comprises reducing an amount of regenerative torque of a rear wheel drive motor when the rear wheel drive is providing power to the power storage device.

reducing, by the controller, the transmission input torque during a power-on upshift to a transmission transient upper threshold torque that is a function of the recorded transmission torque ratio, the transmission torque ratio under the new gear, the transmission inertia, and the duration of the desired transmission upshift; and

the torque capacity of the oncoming clutch is commanded by the controller in response to the torque ratio of the transmission at which the transmission engages the new gear and in response to the recorded torque ratio of the transmission.

According to one embodiment of the invention, the method further comprises commanding a torque capacity of the oncoming clutch in response to the estimated transmission input torque and the estimated equivalent transmission input torque.

According to one embodiment of the invention the equivalent transmission torque estimated in the method is responsive to the torque of the rear wheel drive electric machine or of a motor arranged directly downstream of the transmission or an electric machine comprising a separate drive shaft.

According to one embodiment of the invention, the estimated transmission input torque in the method is responsive to transmission clutch slip.

According to one embodiment of the invention, the method reduces transmission input torque by reducing torque of a rear wheel drive motor when the rear wheel drive is providing positive torque to the driveline.

According to one embodiment of the invention, the method wherein reducing the transmission input torque comprises providing regenerative braking torque by a rear wheel drive motor.

According to one embodiment of the invention, the method wherein reducing the transmission input torque includes reducing the engine torque and the integrated starter/generator torque without adjusting the regenerative braking torque of the rear wheel drive motor when the rear wheel drive motor is providing regenerative braking torque.

adjusting, by the controller, a transmission instantaneous lower limit torque threshold in response to a recorded transmission torque ratio in response to the torque capacity of the offgoing clutch and the estimated transmission input torque, the transmission torque ratio at the old gear, and the uncorrected transmission input torque; and

the torque of the engine is adjusted by the controller in response to the transmission instantaneous lower limit torque threshold.

According to one embodiment of the invention, the method further comprises adjusting a torque capacity of the transmission clutch in response to the recorded transmission torque ratio.

In another expression, the method further includes providing the recorded torque ratio during the engine start in response to clutch torque capacities of the two transmission clutches.

According to one embodiment of the invention, the clutch torque capacities of the two transmission clutches are non-zero in the method.

According to one embodiment of the invention, the method further comprises recording the torque ratio in response to torque ratios of the two transmissions.

According to an embodiment of the invention, the first of the two torque ratios in the method is the torque ratio of the transmission operating at the desired gear.

By reducing the transmission input torque during the shift, driveline torque disturbances that may occur during the inertia phase of a power-on upshift may be reduced. Transmission input torque may be reduced by the engine, an integrated starter/generator, or a rear wheel drive motor. The amount of reduction in transmission input torque may compensate for the amount of increase in transmission output torque provided during the inertia phase of the power-on upshift. Additionally, the torque capacity of the oncoming clutch may be adjusted such that a consistent transmission output torque is provided regardless of whether the rear wheel drive provides positive or negative torque to the driveline.

The present description may provide several advantages. In particular, the method may improve transmission shift feel during a power upshift condition. In addition, driveline torque disturbances associated with transmission shifting may be reduced such that vehicle occupants may perceive reduced driveline noise, vibration, and harshness. Additionally, the transmission clutch torque capacity may further improve transmission shifting in response to the recorded transmission torque ratio.

It should be understood that the summary above is provided to introduce in simplified form a selection of concepts that are further described in the detailed description. It is not meant to identify key or essential features of the claimed subject matter, the scope of which is defined uniquely by the claims that follow the detailed description. Furthermore, the claimed subject matter is not limited to implementations that solve any disadvantages noted above or in any part of this disclosure.

Drawings

FIG. 1A is a schematic illustration of a hybrid vehicle powertrain;

FIG. 1B is a schematic illustration of an engine of a hybrid vehicle powertrain;

FIG. 1C is a schematic illustration of an alternative hybrid vehicle powertrain;

FIG. 2 is a schematic diagram of a hybrid vehicle powertrain including a controller for various powertrain components;

FIG. 3 is a schematic illustration of a dual clutch transmission in a hybrid vehicle powertrain;

FIG. 4 is a flow chart of a shift method of the transmission;

5-9 show graphs of an exemplary transmission shift according to the method of FIG. 4; and

10-12 illustrate exemplary methods for determining transmission torque ratios to facilitate transmission shifting.

Detailed Description

The following embodiments relate to systems and methods for operating a powertrain of a hybrid vehicle. 1A-3 illustrate an exemplary hybrid vehicle system including a powertrain having a motor, an integrated starter/generator, a dual clutch transmission, and a rear wheel drive arrangement having an electric machine disposed downstream of the dual clutch transmission. FIG. 4 illustrates a method for controlling transmission shifting for a hybrid vehicle. 5-9, a hybrid vehicle may be shifted according to the method of FIG. 4. Transmission shifting may be based at least in part on transmission torque ratios as described in the methods of FIGS. 10-12.

FIG. 1A illustrates an exemplary vehicle propulsion system 100 for a vehicle 121. The vehicle propulsion system 100 includes at least two power sources including an internal combustion engine 110 and an electric motor 120. The electric machine 120 may be configured to utilize or consume a different energy source than the engine 110. For example, the engine 110 may consume a liquid fuel (e.g., gasoline) to produce an engine output, and the motor 120 may consume electrical energy to produce a motor output. As such, a vehicle having propulsion system 100 may be referred to as a Hybrid Electric Vehicle (HEV). Throughout the description of FIG. 1A, the mechanical connections between the various components are shown in solid lines, while the electrical connections between the various components are shown in dashed lines.

The vehicle propulsion system 100 has a front axle (not shown) and a rear axle 122. In some examples, the rear axle may include two axle shafts, such as a first axle shaft 122a and a second axle shaft 122b. The vehicle propulsion system 100 also has front wheels 130 and rear wheels 131. The rear axle 122 is connected to the motor 120 and the transmission 125 through a drive shaft 129. The rear axle 122 may be driven purely electrically and solely by the electric machine 120 (e.g., electric-only drive or propulsion mode, engine not combusting air and fuel or rotating), in a hybrid fashion by the electric machine 120 and the engine 110 (e.g., parallel mode), or solely by the engine 100 (e.g., engine-only propulsion mode), in a purely internal combustion engine operating mode. The rear wheel drive device 136 may transmit power from the engine 110 or the motor 120 to the shaft 122, thereby causing the drive wheels 131 to rotate. Rear wheel drive 136 may include a gear set, a differential 193, and an electronically controlled differential clutch 191 that regulates torque transfer to

shafts

122a and 122b. In some examples, the electronically controlled differential clutch 191 may transfer the clutch torque capacity of the electronically controlled differential clutch (e.g., the amount of torque that the clutch may transfer, and which may increase in response to increasing the force applied to engage the clutch) over the CAN bus 299. When the electronically controlled differential clutch is disengaged, the torque transferred to

shafts

122a and 122b may be equal. When electronically controlled differential clutch 191 is partially engaged (e.g., slipped such that the rotational speed input to the clutch is different than the rotational speed of the clutch output) or engaged, the torque transferred to shaft 122a may be different than the torque transferred to shaft 122b. The rear wheel drive 136 may also include one or more clutches (not shown) to decouple the transmission 125 and the electric machine 120 from the wheels 131. The rear wheel drive 136 may be directly connected to the motor 120 and the shaft 122. In some examples, a motor disposed directly downstream of the transmission 125 in the direction of positive torque flow from the engine 110 may replace the rear wheel drive 136.

Transmission 125 is shown in fig. 1A as being connected between engine 110 and electric machine 120, which is assigned to rear axle 122. In one example, transmission 125 is a Dual Clutch Transmission (DCT). In examples where the transmission 125 is a DCT, the DCT may include a first clutch 126, a second clutch 127, and a gearbox 128.DCT125 outputs torque to drive shaft 129, thereby providing torque to wheels 131. As will be discussed in further detail below with reference to fig. 3, the transmission 125 may be shifted by selectively disengaging and engaging the first clutch 126 and the second clutch 127.

The electric machine 120 may receive electrical power from an on-board electrical energy storage device 132. Further, the electric machine 120 may provide a generator function for converting engine output or kinetic energy of the vehicle into electrical energy, which may be stored in the electrical energy storage device 132 for subsequent use by the electric machine 120 or the integrated starter/generator 142. The first inverter system controller (ISC 1) 134 may convert the alternating current generated by the motor 120 into direct current to be stored in the electric energy storage device 132, and vice versa. The electrical energy storage device 132 may be a battery, capacitor, inductor, or other electrical energy storage device.

In some examples, the electrical energy storage device 132 may be configured to store electrical energy that may be supplied to other electrical loads (other than motors) resident on the vehicle, including cabin heating and air conditioning systems, engine starting systems, headlamps, cabin audio and video systems, and the like.

The control system 14 may be in communication with one or more of the engine 110, the electric machine 120, the energy storage device 132, the integrated starter/generator 142, the transmission 125, and the like. The control system 14 may receive sensory feedback from one or more of the engine 110, the electric machine 120, the energy storage device 132, the integrated starter/generator 142, the transmission 125, and the like. Further, the control system 14 may send control signals to one or more of the engine 110, the motor 120, the energy storage device 132, the transmission 125, etc., in response to the sensory feedback. Control system 14 may receive an indication of the operator requested vehicle propulsion system output from operator 102 or an autonomous controller. For example, control system 14 may receive sensory feedback from a pedal position sensor 194 in communication with pedal 192. Pedal 192 may be schematically referred to as an accelerator pedal. Similarly, control system 14 may receive an indication of operator requested vehicle braking via operator 102 or an autonomous controller. For example, control system 14 may receive sensory feedback from a pedal position sensor 157 in communication with brake pedal 156.

Energy storage device 132 may periodically receive electrical energy from a power source 180 (e.g., a stationary electrical grid) that is present outside of the vehicle (e.g., not part of the vehicle), as indicated by arrow 184. As a non-limiting example, the vehicle propulsion system 100 may be configured for a plug-in hybrid electric vehicle (PHEV), whereby electrical energy may be supplied from the power source 180 to the energy storage device 132 via the power transmission cable 182. During a recharging operation of the energy storage device 132 by the power source 180, the power transfer cable 182 may electrically connect the energy storage device 132 and the power source 180. In some examples, a power supply 180 may be connected at the input port 150. Further, in some examples, the charge status indicator 151 may display the charge status of the energy storage device 132.

In some examples, power from the power source 180 may be received by the charger 152. For example, the charger 152 may convert alternating current from the power source 180 to Direct Current (DC) for storage in the energy storage device 132. In addition, the DC/DC converter 153 may convert a direct current source from the charger 152 from one voltage to another voltage. In other words, the DC/DC converter 153 may function as one type of power converter.

When the vehicle propulsion system is operating to propel the vehicle, the power transfer cable 182 may be disconnected between the power source 180 and the energy storage device 132. Control system 14 may identify and/or control an amount of electrical energy stored in an energy storage device, which may be referred to as a state of charge (SOC).

In other examples, where electrical energy may be received wirelessly at energy storage device 132 from power source 180, power transfer cable 182 may be omitted. For example, the energy storage device 132 may receive electrical energy from the power source 180 via one or more of electromagnetic induction, radio waves, and electromagnetic resonance. As such, it should be appreciated that any suitable method may be used to recharge energy storage device 132 from a power source that does not form part of the vehicle. In this manner, the electric machine 120 may propel the vehicle by utilizing an energy source other than the fuel utilized by the engine 110.

The electrical energy storage device 132 includes an electrical energy storage device controller 139 and a power distribution module 138. The electrical energy storage device controller 139 may provide charge equalization among the energy storage elements (e.g., battery cells) and communicate with other vehicle controllers (e.g., controller 12). The power distribution module 138 controls the flow of power to and from the electrical energy storage device 132.

The vehicle propulsion system 100 may also include an ambient temperature/humidity sensor 198, as well as sensors dedicated to indicating the occupancy state of the vehicle, such as the onboard camera 105, the seat load sensor 107, and the door sensing technology device 108. The vehicle system 100 may also include an inertial sensor 199. Inertial sensors 199 may include one or more of the following sensors: a longitudinal sensor, a lateral sensor, a vertical sensor, a yaw sensor, a roll sensor, and a pitch sensor (e.g., an accelerometer). Shown as the axes of yaw, pitch, roll, lateral acceleration, and longitudinal acceleration. As one example, the inertial sensor 199 may be connected to a Restraint Control Module (RCM) (not shown) of the vehicle, which RCM contains subsystems of the control system 14. The control system may adjust engine output and/or wheel brakes in response to sensor 199 to increase vehicle stability. In another example, the control system may adjust the active suspension system 111 in response to input from the inertial sensor 199. Active suspension system 111 may include an active suspension system having hydraulic, electrical, and/or mechanical devices, and an active suspension system that controls vehicle height based on a single corner (e.g., vehicle height controlled individually for four corners), vehicle height based on individual axles (e.g., front axle and rear axle vehicle height), or uniform vehicle height for the entire vehicle. Data from the inertial sensor 199 may also be communicated to the controller 12, or alternatively, the sensor 199 may be electrically connected to the controller 12.

One or more Tire Pressure Monitoring Sensors (TPMS) may be connected to the tires of one or more wheels in the vehicle. For example, fig. 1A shows a tire pressure sensor 197 connected to the wheel 131 and configured to monitor the pressure in the tire of the wheel 131. Although not explicitly shown, it should be understood that each of the four tires indicated in fig. 1A may include one or more tire pressure sensors 197. Further, in some examples, the vehicle propulsion system 100 may include a pneumatic control unit 123. The pneumatic control unit may receive information about the tire pressure from the tire pressure sensor 197 and transmit the tire pressure information to the control system 14. Based on the tire pressure information, the control system 14 may command the pneumatic control unit 123 to inflate or deflate the tires of the wheels. Although not explicitly shown, it should be understood that the pneumatic control unit 123 may be used to inflate or deflate a tire associated with any of the four wheels shown in fig. 1A. For example, in response to an indication of a decrease in tire pressure, control system 14 may command pneumatic control system unit 123 to inflate one or more tires. Alternatively, in response to an indication of an increase in tire pressure, control system 14 may command pneumatic control system unit 123 to deflate one or more tires. In both examples, the pneumatic control system unit 123 may be used to inflate or deflate the tire to the optimal tire pressure rating for the tire, which may extend tire life.

One or more Wheel Speed Sensors (WSS) 195 may be connected to one or more wheels of the vehicle propulsion system 100. The wheel speed sensor may detect the rotational speed of each wheel. Such an example of a WSS may include a permanent magnet type sensor.

The vehicle propulsion system 100 may also include an accelerometer 20. Vehicle propulsion system 100 may also include an inclinometer 21.

The vehicle propulsion system 100 may also include a starter 140. The starter 140 may include an electric motor, a hydraulic motor, etc., and may be used to rotate the engine 110 in order to start the engine 110 to operate under its own power.

Vehicle propulsion system 100 may also include a Braking System Control Module (BSCM) 141. In some examples, BSCM141 may incorporate an anti-lock braking system such that wheels (e.g., 130, 131) may remain in tractive contact with the road surface while braking, which may thus prevent the wheels from locking up, thereby preventing slip, depending on driver input. In some examples, the BSCM may receive input from wheel speed sensors 195.

The vehicle propulsion system 100 may also include a belt-type integrated starter/generator (BISG) 142. The BISG may generate electrical power when engine 110 is running, where the generated electrical power may be used to supply electrical devices and/or charge on-board storage device 132. As shown in fig. 1A, a second inverter system controller (ISC 2) 143 may receive ac power from the BISG142 and may convert the ac power generated by the BISG142 to dc power for storage in the energy storage device 132. The integrated starter/generator 142 may also provide torque to the engine 110 during engine starting or other conditions to supplement engine torque.

In some examples, the vehicle propulsion system 100 may include one or more

electric machines

135a and 135b for propelling the vehicle 121 or providing regenerative braking via the front wheels 130. The third inverter (ISC 3) 147a may convert the alternating current generated by the motor 135a into direct current to be stored in the electric energy storage device 132, or supply the alternating current to the motor 135a to propel the vehicle 121. Likewise, the fourth inverter (ISC 4) 147a may convert the alternating current generated by the motor 135b into direct current to be stored in the electric energy storage device, or supply the alternating current to the motor 135b to propel the vehicle 121. The

motors

135a and 135b may be collectively referred to as a front wheel motor. Alternatively, as shown in FIG. 1C, a single front wheel motor may drive and/or provide regenerative braking to both front wheels 130.

The vehicle propulsion system 100 may also include a Power Distribution Box (PDB) 144.PDB144 may be used to route power supplies throughout various circuits and accessories in the vehicle's electrical system.

The vehicle propulsion system 100 may also include a High Current Fuse Box (HCFB) 145 and may contain various fuses (not shown) for protecting the wiring and electrical components of the vehicle propulsion system 100.

The vehicle propulsion system 100 may also include a Motor Electronic Coolant Pump (MECP) 146. The MECP146 may be used to circulate a coolant to dissipate heat generated by at least the electric machine 120 and the electronic systems of the vehicle propulsion system 100. For example, the MECP may receive power from the on-board energy storage device 132.

The controller 12 may form part of a control system 14. In some examples, the controller 12 may be a single controller of the vehicle. The control system 14 is shown receiving information from a plurality of sensors 16 (various examples of which sensors 16 are described herein) and sending control signals to a plurality of actuators 81 (various examples of which actuators 81 are described herein). As one example, the sensors 16 may include a tire pressure sensor 197, a wheel speed sensor 195, an ambient temperature/humidity sensor 198, an onboard camera 105, a seat load sensor 107, a door sensing technology device 108, an inertial sensor 199, and the like. In some examples, sensors associated with engine 110, transmission 125, electric machine 120, etc. may communicate information to controller 12 regarding various states of engine, transmission, and motor operation, as will be discussed in further detail with reference to fig. 1B, 2, and 3.

The vehicle propulsion system 100 may also include a Positive Temperature Coefficient (PTC) heater 148. For example, the PTC heater 148 may comprise a ceramic material such that when the resistance is low, the ceramic material may accept a large amount of current, which may cause the ceramic element to warm up quickly. However, as the element warms and reaches the threshold temperature, the resistance may become very large and thus may not continue to generate much heat. Because of this, the PTC heater 148 may be self-regulating and may have a good level of over-temperature protection.

The vehicle propulsion system 100 may also include an air conditioner compressor module 149 for controlling an electric air conditioner compressor (not shown).

The vehicle propulsion system 100 may also include a Vehicle Auditory Sounder (VASP) 154 for pedestrians. For example, the VASP154 may be configured to produce audible sound through the sound generator 155. In some examples, the audible sound generated by the VASP154 in communication with the sound generator 155 may be activated in response to the vehicle operator triggering the sound, or automatically in response to the engine speed falling below a threshold or a pedestrian being detected.

The vehicle propulsion system 100 may also include an in-vehicle navigation system 17 (e.g., a global positioning system) located on the dashboard 19, with which in-vehicle navigation system 17 an operator of the vehicle may interact. The navigation system 17 may include one or more location sensors for assisting in estimating the location (e.g., geographic coordinates) of the vehicle. For example, the in-vehicle navigation system 17 may receive a signal from a GPS satellite (not shown) and identify the geographic location of the vehicle from the signal. In some examples, the geographic location coordinates may be communicated to the controller 12.

The instrument cluster 19 may also include a display system 18, the display system 18 configured to display information to a vehicle operator. By way of non-limiting example, the display system 18 may include a touch screen, or Human Machine Interface (HMI), display that enables the vehicle operator to view graphical information and enter commands. In some examples, display system 18 may be wirelessly connected to the internet (not shown) through a controller (e.g., 12). As such, in some examples, the vehicle operator may communicate with an internet site or software application (app) through display system 18.

The instrument cluster 19 may also include an operator interface 15 through which a vehicle operator may adjust the operating conditions of the vehicle. Specifically, the operator interface 15 may be configured to initiate and or terminate operation of the vehicle driveline (e.g., engine 110, BISG142, DCT125, electric machine 120) based on operator input. Various exemplary operator ignition interfaces 15 may include interfaces that require physical devices, such as active keys, that may be inserted into the operator ignition interface 15 to start the engine 110 and start the vehicle, or may be removed to shut down the engine 110 and shut down the vehicle. Other examples may include a passive key communicatively connected to the operator ignition interface 15. The passive key may be configured as an electronic key fob or smart key that operates the vehicle engine 110 without having to be inserted into or removed from the ignition interface 15. Of course, the passive key may need to be located inside or near the vehicle (e.g., within a threshold distance of the vehicle). Yet another example may additionally or alternatively use a start/stop button that is manually depressed by an operator to start or shut down engine 110 and start or shut down the vehicle. In other examples, a remote computing device (not shown), such as a cellular telephone, or smartphone-based system, may initiate a remote engine start, where the user's cellular telephone sends data to the server, and the server communicates with the vehicle controller 12 to start the engine.

Referring to FIG. 1B, a detailed view of the internal combustion engine 110 is shown, the internal combustion engine 110 including a plurality of cylinders, one cylinder of which is shown in FIG. 1B. The engine 110 is controlled by an electronic engine controller 111B. Engine 110 includes combustion chamber 30B and cylinder walls 32B with piston 36B disposed therein and coupled to crankshaft 40B. Combustion chamber 30B is shown communicating with intake manifold 44B and exhaust manifold 48B via respective intake valve 52B and exhaust valve 54B. Each intake and exhaust valve may be operated by an intake cam 51B and an exhaust cam 53B. The position of the intake cam 51B may be determined by an intake cam sensor 55B. The position of exhaust cam 53B may be determined by exhaust cam sensor 57B. The intake cam 51B and the exhaust cam 53B are movable relative to the crankshaft 40B. The intake valve may be deactivated by the intake valve deactivation mechanism 59B and maintained in a closed state. The exhaust valves may be deactivated by an exhaust valve deactivation mechanism 58B and maintained in a closed state.

Fuel injector 66B is shown configured to inject fuel directly into cylinder 30B, which is known to those skilled in the art as direct injection. Alternatively, fuel may be injected to the intake port, which is known to those skilled in the art as port injection. Fuel injector 66B delivers liquid fuel in proportion to the pulse width of the signal from engine controller 111B. Fuel is delivered to fuel injector 66B by fuel system 175B, which includes a tank and a pump. Additionally, intake manifold 44B is shown communicating with an optional electronic throttle 62B (e.g., a butterfly valve), which electronic throttle 62B adjusts the position of throttle plate 64B to control the flow of air from air filter 43B and intake port 42B to intake manifold 44B. Throttle 62B regulates air flow from air filter 43B in engine intake 42B to intake manifold 44B. In some examples, throttle 62B and throttle plate 64B may be disposed between intake valve 52B and intake manifold 44B such that throttle 62B is a port throttle.

Distributorless ignition system 88B provides an ignition spark to combustion chamber 30B via spark plug 92B in response to engine controller 111B. A wide range exhaust gas oxygen (UEGO) sensor 126B is shown coupled to exhaust manifold 48B upstream of catalytic converter 70B in the direction of exhaust gas flow. Alternatively, a two-state exhaust gas oxygen sensor may be substituted for UEGO sensor 126B.

In one example, converter 70B may include a plurality of catalyst bricks (catalysts). In another example, multiple emission control devices, each having multiple bricks, may be used. In one example, converter 70B may be a three-way type catalyst.

The engine controller 111B shown in fig. 1B is a general microcomputer including: a microprocessor unit (CPU) 102B, an input/output port (I/O) 104B, a Read Only Memory (ROM) 106B (e.g., non-transitory memory), a Random Access Memory (RAM) 108B, a Keep Alive Memory (KAM) 110B, and a conventional data bus. Other controllers mentioned herein may have similar processor and memory configurations. Engine controller 111B is shown receiving various signals from sensors connected to engine 110, including, in addition to those signals previously discussed: engine Coolant Temperature (ECT) from temperature sensor 112B coupled to cooling sleeve 114B, a measurement of engine manifold pressure (MAP) from pressure sensor 122B coupled to intake manifold 44B, an engine position from hall effect sensor 118B sensing the position of crankshaft 40B, a measurement of air mass entering the engine from sensor 120B, and a measurement of throttle position from sensor 58B. Air pressure processed by engine controller 111B may also be sensed (sensor not shown). In a preferred aspect of the present description, the engine position sensor 118B generates a predetermined number of equally spaced pulses every revolution of the crankshaft from which engine speed (RPM) can be determined. The engine controller 111B may receive input from a human/machine interface 115B (e.g., buttons or a touch screen display).

During operation, each cylinder within engine 110 typically undergoes a four-stroke cycle: the cycle includes an intake stroke, a compression stroke, an expansion stroke, and an exhaust stroke. Generally, during the intake stroke, exhaust valve 54B closes and intake valve 52B opens. Air is introduced into combustion chamber 30B through intake manifold 44B, and piston 36B moves to the bottom of the cylinder to increase the volume within combustion chamber 30B. The position of piston 36B near the bottom of the cylinder and at the end of its stroke (e.g., when combustion chamber 30B is at its largest volume) is typically referred to by those skilled in the art as Bottom Dead Center (BDC). During the compression stroke, intake valve 52B and exhaust valve 54B are closed. Piston 36B moves toward the cylinder head to compress the air within combustion chamber 30B. The position at which piston 36B is at the end of its stroke and closest to the cylinder head (e.g., when combustion chamber 30B is at its smallest volume) is commonly referred to by those skilled in the art as Top Dead Center (TDC). In a process hereinafter referred to as injection, fuel is introduced into the combustion chamber. In a process hereinafter referred to as ignition, the injected fuel is ignited by a known ignition device such as a spark plug 92B, resulting in combustion. During the expansion stroke, the expanding gases push piston 36B back to BDC. Crankshaft 40B converts piston motion into rotational torque of the shaft. Finally, during the exhaust stroke, the exhaust valve 54B opens to release the combusted air-fuel mixture to exhaust manifold 48B and the piston returns to TDC. It should be noted that the above is shown merely as an example, and that intake and exhaust valve opening and/or closing timings may vary, for example, to provide positive or negative valve overlap, late intake valve closing, or various other examples.

FIG. 1C is a schematic illustration of an alternative hybrid vehicle powertrain. Components of the hybrid vehicle powertrain shown in FIG. 1C that are identical to components shown in FIG. 1A are identified using the same reference numerals as used in FIG. 1A. Features characteristic of the configuration of FIG. 1C are identified with new feature reference numerals. In this configuration, the hybrid vehicle powertrain includes a front axle 133. The motor 135c may provide positive or negative torque to the front wheels 130 through a front wheel differential 137. In some examples, the motor 135c and the differential 137 are considered to be part of the front axle 133. Thus, the front axle 133 may provide regenerative braking or torque to propel the vehicle 121. Further, the electric machine 135c may receive power from the electrical energy storage device 132 or provide power to the electrical energy storage device 132. The front axle 133 may be referred to as an independent drive axle. The other components shown in FIG. 1C may operate as previously described.

Fig. 2 is a block diagram of a vehicle 121 including a powertrain or driveline 200. The powertrain of fig. 2 includes an engine 110 shown in fig. 1A-1C. Other components of fig. 2 that are identical to those of fig. 1A and 1C are identified with the same reference numerals and will be discussed in detail below. The powertrain system 200 is shown to include a vehicle system controller 12, an engine controller 111B, a motor controller 252, a transmission controller 254, an energy storage device controller 253, and a brake controller 141 (also referred to herein as a brake system control module). The controller may communicate over a Controller Area Network (CAN) 299. Each of the controllers may provide information to the other controllers, such as torque output limits (e.g., no more torque output by the controlled device or component), torque input limits (e.g., no more torque input by the controlled device or component), torque output of the controlled device, sensor and actuator data, diagnostic information (e.g., information about a degraded transmission, information about a degraded engine, information about a degraded motor, information about a degraded brake). In addition, the vehicle system controller 12 may provide commands to the engine controller 111B, the motor controller 252, the transmission controller 254, and the brake controller 141 to implement driver input requests and other requests based on vehicle operating conditions.

For example, the vehicle system controller 12 may request a desired wheel torque or wheel power level to provide a desired vehicle deceleration rate in response to the driver releasing the accelerator pedal and the vehicle speed decreasing. The desired wheel torque is provided by the vehicle system controller 12 requesting a first braking torque from the motor controller 252 and a second braking torque from the brake controller 141, the first and second torques providing the desired braking torque at the vehicle wheels 131.

In other examples, the division controlling the driveline devices may be different than the division shown in FIG. 2. For example, a single controller may replace the vehicle system controller 12, the engine controller 111B, the motor controller 252, the transmission controller 254, and the brake controller 141. Alternatively, the vehicle system controller 12 and the engine controller 111B may be one device, while the motor controller 252, the transmission controller 254, and the brake controller 141 may be separate controllers.

In this example, the powertrain 200 may be powered by the engine 110 and the electric machine 120. In other examples, engine 110 may be omitted. The engine 110 may be started with an engine starter (e.g., starter 140), by a belt-based integrated starter/generator (BISG) 142, or by the electric machine 120. In some examples, BISG142 may be directly connected to the engine crankshaft at either end (e.g., the front end or the rear end) of the crankshaft. The electric machine 120 (e.g., a high voltage electric machine operating at greater than 30 volts) is also referred to herein as an electric machine, a motor, and/or a generator. Further, the torque of the engine 110 may be adjusted by a torque actuator 204, such as a fuel injector, a throttle, or the like.

BISG142 is mechanically coupled to engine 110 by a belt 231. The BISG142 may be connected to a crankshaft (not shown) or a camshaft (not shown). The BISG142 may operate as a motor when supplied with electrical power by the electrical energy storage device 132 (also referred to herein as the on-board energy storage device 132). Additionally, the BISG142 may also operate as a generator that supplies electrical power to the electrical energy storage device 132.

The powertrain 200 includes an engine 110 mechanically coupled to a Dual Clutch Transmission (DCT) 125 via a crankshaft 40B. The DCT125 includes a first clutch 126, a second clutch 127, and a gearbox 128.DCT125 outputs torque to shaft 129 to provide torque to wheels 131. The transmission controller 254 selectively disengages and engages the first clutch 126 and the second clutch 127 to shift the DCT 125.

The gearbox 128 may include a plurality of gears. One clutch, such as the first clutch 126, may control the odd gear 261 (e.g., first gear, third gear, fifth gear, and reverse gear), while another clutch, such as the second clutch 127, may control the even gear 262 (e.g., second gear, fourth gear, and sixth gear). By utilizing such an arrangement, the gears can be changed without interrupting the power flow from the engine 110 to the dual clutch transmission 125.

Electric machine 120 may be operated in a regenerative mode to provide torque to powertrain 200 or to convert powertrain torque to electrical energy for storage in electrical energy storage device 132. Additionally, the electric machine 120 may convert kinetic energy of the vehicle into electric energy for storage in the electric energy storage device 132. The electric machine 120 is in electrical communication with an energy storage device 132. The motor 120 has a higher output torque capacity than the starter (e.g., 140) or BISG142 shown in fig. 1A. Further, motor 120 directly drives drivetrain 200 or is driven directly by drivetrain 200.

The electrical energy storage device 132 (e.g., a high voltage battery or power source) may be a battery, a capacitor, or an inductor. The electric machine 120 is mechanically connected to the wheels 131 and the dual clutch transmission through a gear set in a rear wheel drive 136 (shown in fig. 1A). The electric machine 120 may provide positive or negative torque to the powertrain 200 by operating as a motor or a generator as directed by the electric machine controller 252.

Further, frictional forces may be applied to the wheels 131 by engaging the friction wheel brakes 218. In one example, the friction wheel brakes 218 may be engaged in response to the driver pressing his foot on a brake pedal (e.g., pedal 192) and/or in response to instructions within the brake controller 141. Further, the brake controller 141 may apply the brakes 218 in response to information and/or requests issued by the vehicle system controller 12. In the same manner, the frictional force applied to the wheels 131 may be reduced by disengaging the wheel brakes 218 in response to the driver releasing his foot from the brake pedal, brake controller commands, and/or vehicle system controller commands and/or information. For example, the vehicle brakes may apply frictional forces to the wheels 131 through the controller 141 as part of an automatic engine stop process.

The vehicle system controller 12 may also communicate vehicle suspension system settings to the suspension controller 280. The suspension system (e.g., 111) of vehicle 121 can be tuned to critically damped, over-damped, or under-damped vehicle suspension systems by variable damper 281.

Thus, torque control of various powertrain components may be monitored by the vehicle system controller 12, with local torque control of the engine 110, transmission 125, motor 120, and brake 218 being provided by the engine controller 111B, motor controller 252, transmission controller 254, and brake controller 141.

As one example, engine torque output may be controlled by adjusting a combination of spark timing, fuel pulse width, fuel pulse timing, and/or air induction, by controlling throttle (e.g., 62B) opening, and/or valve timing, valve lift, and boost for a turbocharged or supercharged engine. In the case of a diesel engine, controller 12 may control engine torque output by controlling a combination of fuel pulse width, fuel pulse timing, and air charge. In all cases, engine control may be performed on a cylinder-by-cylinder basis to control engine torque output.

The motor controller 252 may control the torque output and power generated by the motor 120 by regulating the current flowing into and out of the field windings and/or armature windings of the motor 120, as is known in the art.

The transmission controller 254 may receive transmission output shaft torque from a torque sensor 272. Alternatively, the sensor 272 may be a position sensor or a torque and position sensor. If the sensor 272 is a position sensor, the transmission controller 254 may count the shaft position pulses over a predetermined time interval to determine the transmission output shaft speed. The transmission controller 254 may also differentiate between transmission output shaft speeds to determine transmission output shaft acceleration. The transmission controller 254, engine controller 111B, and vehicle system controller 12 may also receive additional transmission information from sensors 277, which sensors 277 may include, but are not limited to, a pump output line pressure sensor, a transmission hydraulic pressure sensor (e.g., a gear clutch fluid pressure sensor), a motor temperature sensor, a BISG temperature sensor, a shift selector position sensor, a synchronizer position sensor, and an ambient temperature sensor. The transmission controller may also receive a requested transmission state (e.g., a requested gear or park mode) from a shift selector 279, which may be a lever, switch or other device.

The brake controller 141 receives wheel speed information through the wheel speed sensor 195 and receives a braking request from the vehicle system controller 12. The brake controller 141 may also receive brake pedal position information directly or through the CAN299 from brake pedal sensors (e.g., 157) shown in fig. 1A. The brake controller 141 may provide braking in response to wheel torque commands from the vehicle system controller 12. Brake controller 141 may also provide anti-lock and vehicle stability braking to improve vehicle braking and stability. Because of this, the brake controller 141 may provide the vehicle system controller 12 with a wheel torque limit (e.g., not exceeding a threshold negative wheel torque) such that a negative motor torque does not cause the wheel torque limit to be exceeded. For example, if the controller 12 issues a negative wheel torque limit of 50N-m, the motor torque may be adjusted to provide a negative torque at the wheels of less than 50N-m (e.g., 49N-m), including accounting for a transmission gear shift.

Positive torque may be transmitted to the wheels 131 in a direction starting at the engine 110 and ending at the wheels 131. Thus, depending on the direction of positive torque transfer in the drive train 200, the engine 110 is arranged in the drive train 200 upstream of the transmission 125. Transmission 125 is disposed upstream of motor 120, and BISG142 may be disposed upstream of engine 110, or downstream of engine 110 and upstream of transmission 125.

Fig. 3 shows a detailed view of a Dual Clutch Transmission (DCT) 125. The engine crankshaft 40B is shown connected to the clutch housing 393. Alternatively, a shaft may connect crankshaft 40B to clutch housing 393. Clutch housing 393 may rotate in accordance with the rotation of crankshaft 40B. The clutch housing 393 may include the first clutch 126 and the second clutch 127. Further, each of the first and

second clutches

126, 127 has an associated first and second clutch plate 390, 391, respectively. In some examples, the clutch may comprise a wet clutch or a dry plate clutch immersed in oil (for cooling). Engine torque may be transferred from clutch housing 393 to either first clutch 126 or second clutch 127. The first transmission clutch 126 transfers torque between the engine 110 (shown in fig. 1A) and a first transmission input shaft 302. As such, clutch housing 393 may be referred to as the input side of first transmission clutch 126, and 126A may be referred to as the output side of first transmission clutch 126. The second transmission clutch 127 transfers torque between the engine 110 (shown in FIG. 1A) and the second transmission input shaft 304. As such, clutch housing 393 may be referred to as the input side of the second transmission clutch 127, and 127A may be referred to as the output side of the second transmission clutch 127.

As described above, the gearbox 128 may include a plurality of gears. There are two transmission input shafts, including a first transmission input shaft 302 and a second transmission input shaft 304. The second transmission input shaft 304 is hollow, while the first transmission input shaft 302 is solid and is coaxially located within the second transmission input shaft 304. As one example, the first transmission input shaft 302 can have a plurality of fixed gears. For example, the first transmission input shaft 302 can include a first fixed gear 306 for receiving a first gear 320, a third fixed gear 310 for receiving a third gear 324, a fifth fixed gear 314 for receiving a fifth gear 329, and a seventh fixed gear 318 for receiving a seventh gear 332. In other words, the first transmission input shaft 302 may be selectively connectable to a plurality of odd-numbered gears. The second transmission input shaft 304 may include a second fixed gear 308 for receiving a second gear 322 or a reverse gear 328, and may also include a fourth fixed gear 316 for receiving a fourth gear 326 or a sixth gear 330. It should be appreciated that both the first transmission input shaft 302 and the second transmission input shaft 304 may be connected to each of the first clutch 126 and the second clutch 127, respectively, by spines (not shown) on the outboard side of each shaft. In a normal, stationary state, each of the first clutch 126 and the second clutch 127 is held disengaged, such as by a spring (not shown) or the like, so that torque from the engine (e.g., 110) is not transferred to the first transmission input shaft 302 or the second transmission input shaft 304 when each of the respective clutches is in the disengaged state. Engine torque may be transferred to the first transmission input shaft 302 in response to engaging the first clutch 126, and engine torque may be transferred to the second transmission input shaft 304 in response to engaging the second clutch 127. During normal operation, the transmission electronics can ensure that only one clutch is engaged at any particular time.

The gearbox 128 may also include a first countershaft 340 and a second countershaft 342. The gears on the first and second countershafts 340, 342 are not fixed, but are free to rotate. In the exemplary DCT125, the first countershaft 340 includes a first gear 320, a second gear 322, a sixth gear 330, and a seventh gear 332. The second countershaft 342 includes a third gear 324, a fourth gear 326, a fifth gear 329, and a reverse gear 328. Both the first and second countershafts 340, 342 may transfer torque to gear 353 through first and second output pinion gears 350, 352, respectively. In this manner, the two layshafts may transmit torque through each of the first and second output pinions 350, 352 to an output shaft 362, wherein the output shaft may transmit torque to the rear wheel drive 136 (shown in fig. 1A), and the rear wheel drive 136 may enable each of the drive wheels (e.g., 131 of fig. 1A) to rotate at different rotational speeds, such as when performing a steering maneuver.

As described above, each of the first gear 320, the second gear 322, the third gear 324, the fourth gear 326, the fifth gear 329, the sixth gear 330, the seventh gear 332, and the reverse gear 328 are not fixed to the countershafts (e.g., 340 and 342), but are free to rotate. Because of this, synchronizers may be used to enable each of the gears to match the rotational speed of the layshaft and may also be used to lock the gears. In the exemplary DCT125, four synchronizers are shown, such as a first synchronizer 370, a second synchronizer 374, a third synchronizer 380, and a fourth synchronizer 384. The first synchronizer 370 includes a corresponding first shift fork 372, the second synchronizer 374 includes a corresponding second shift fork 376, the third synchronizer 380 includes a corresponding third shift fork 378, and the fourth synchronizer 384 includes a corresponding fourth shift fork 382. Each of the shift forks may enable each respective synchronizer to be moved to lock one or more gears or to unlock one or more gears. For example, the first synchronizer 370 may be used to lock the first gear 320 or the seventh gear 332. The second synchronizer 374 can be used to lock the second gear 322 or the sixth gear 330. Third synchronizer 380 may be used to lock third gear 324 or fifth gear 329. The fourth synchronizer 384 may be used to lock the fourth gear 326 or the reverse gear 328. In each case, movement of the synchronizers may be accomplished by moving each of the respective synchronizers to a desired position by a shift fork (e.g., 372, 376, 378, and 382).

Synchronizer shifting by a shift fork may be performed by a Transmission Control Module (TCM) 254 and a shift fork actuator 388, wherein the TCM254 may comprise the TCM254 discussed above with respect to fig. 2. The shift fork actuator may be operated electrically, hydraulically, or a combination of electrically and hydraulically. Hydraulic power may be provided by pump 312 and/or pump 367. The TCM254 may collect input signals from a variety of sensors, evaluate the inputs, and control a variety of actuators accordingly. Inputs used by the TCM254 may include, but are not limited to, transmission gear (P/R/N/D/S/L, etc.), vehicle speed, engine speed and torque, throttle position, engine temperature, ambient temperature, steering angle, brake input, gearbox input shaft speed (for the first transmission input shaft 302 and the second transmission input shaft 304), vehicle attitude (pitch). The TCM may control the actuators through open loop control to achieve adaptive control. For example, adaptive control may enable the TCM254 to identify and adapt clutch engagement points, clutch coefficients of friction, and synchronizer assembly positions. The TCM254 may also adjust the first and second clutch actuators 389, 387 to disengage and engage the first and

second clutches

126, 127. The first and second clutch actuators 389, 387 may be electrically, hydraulically, or a combination thereof. Hydraulic power may be provided by pump 312 and/or pump 367.

Thus, the TCM254 is shown receiving input from various sensors 277. As described above with respect to fig. 2, the various sensors may include a pump output line pressure sensor, a transmission hydraulic pressure sensor (e.g., a gear clutch fluid pressure sensor), a motor temperature sensor, a shifter position sensor, a synchronizer position sensor, and an ambient temperature sensor. The various sensors 277 may also include wheel speed sensors (e.g., 195), engine speed sensors, engine torque sensors, throttle position sensors, engine temperature sensors, steering angle sensors, transmission fork position sensors for detecting the position of shift forks (e.g., 372, 376, 378, 382), and inertial sensors (e.g., 199). As described above with respect to fig. 1A, the inertial sensors may include one or more of the following sensors: longitudinal sensors, lateral sensors, vertical sensors, yaw sensors, roll sensors, and pitch sensors.

The sensors 277 can also include Input Shaft Speed (ISS) sensors, which can comprise magnetoresistive sensors, and wherein each gearbox input shaft can comprise an ISS sensor (e.g., one ISS sensor for the first transmission input shaft 302, and one ISS sensor for the second transmission input shaft 304). The sensor 277 may also include an output shaft speed sensor (OSS), which may include a magnetoresistive sensor, and may be attached to the output shaft 362. The sensors 277 may also include a transmission gear (TR) sensor.

DCT125 may be understood to function as described herein. For example, when the first clutch 126 is actuated to engage, engine torque may be supplied to the first transmission input shaft 302. When the first clutch 126 is engaged, it should be understood that the second clutch 127 is disengaged, and vice versa. Based on which gear is locked when the first clutch 126 is engaged, power may be transmitted through the first transmission input shaft 302 to the first countershaft 340 or the second countershaft 342, and may also be transmitted through the first pinion gear 350 or the second pinion gear 352 to the output shaft 362. Alternatively, when the second clutch 127 is engaged, power may be transmitted to the first countershaft 340 or the second countershaft 342 through the second transmission input shaft 304, and power may also be transmitted to the output shaft 362 through the first pinion gear 350 or the second pinion gear 352, depending on which gear is locked. It will be appreciated that when torque is transferred to one layshaft (e.g., first output shaft 340), the other layshaft (e.g., second output shaft 342) may continue to rotate even though only one shaft is directly driven by the input. More specifically, the unengaged shaft (e.g., the second countershaft 342) may continue to rotate because it is indirectly driven by the output shaft 362 and the corresponding pinion (e.g., the second pinion 352).

The DCT125 may be capable of pre-selecting gears, which may thus enable rapid shifting between gears with minimal torque loss during a shift. As an example, when the first gear 320 is locked by the first synchronizer 370, and wherein the first clutch 126 is engaged (and the second clutch 127 is disengaged), power may be transferred from the engine to the first input shaft 302 and to the first countershaft 340. When the first gear 320 is engaged, the second gear 322 may be simultaneously locked by the second synchronizer 374. This may cause the second input shaft 304 to rotate because the second gear 322 is locked, wherein the rotational speed of the second input shaft 304 matches the vehicle speed under the second gear. In the alternative where the preselected gear is located on another layshaft (e.g., the second layshaft 342), the layshaft will also rotate as it is driven by the output shaft 362 and pinion gear 352.

When a shift is initiated by the TCM254, only the clutch needs to be actuated to disengage the first clutch 126 and engage the second clutch 127. Further, outside of the TCM control range, engine speed may be reduced to match an upshift. With the second clutch 127 engaged, power may be transmitted from the engine to the second input shaft 304, and to the first countershaft 340, and also to the output shaft 362 via the pinion gear 350. After the shift is completed, the TCM254 can appropriately pre-select the next gear. For example, the TCM254 may pre-select a higher gear or a lower gear based on inputs it receives from various sensors 277. In this manner, a shift may be quickly achieved with minimal loss of engine torque provided to output shaft 362.

The dual clutch transmission 125 may include a park gear 360 in some examples. The parking pawl 363 may face the parking gear 360. The parking pawl 363 may engage the parking gear 360 when the shift control lever is set to park. The engagement of the parking pawl 363 with the parking gear 360 may be achieved by a parking pawl spring 364, or the engagement of the parking pawl 363 with the parking gear 360 may be achieved, for example, by a cable (not shown), a hydraulic piston (not shown), or a motor (not shown). When the parking pawl 363 is engaged with the parking gear 360, the drive wheels (e.g., front wheels 130, rear wheels 131) of the vehicle may be locked. On the other hand, in response to the shift control lever being moved from park to another option (e.g., actuated), the parking pawl 363 may be moved such that the parking pawl 363 may disengage from the parking gear 360.

In some examples, the electric transmission pump 312 may supply hydraulic fluid from the transmission reservoir 311 to compress the spring 364 to release the parking pawl 363 from the parking gear 360. For example, the electrically variable transmission pump 312 may be powered by an onboard energy storage device (e.g., 132). In some examples, the mechanical pump 367 may additionally or alternatively supply hydraulic fluid from the transmission reservoir 311 to compress the spring 364 to release the park pawl 363 from the park gear 360. Although not explicitly shown, a mechanical pump may be driven by the engine (e.g., 110) and may be mechanically connected to the clutch housing 393. In some examples, the parking pawl valve 361 may regulate the flow of hydraulic fluid to the spring 364.

Referring now to fig. 4, an exemplary method for operating a hybrid powertrain to improve transmission shifting is illustrated. The method of fig. 4 may be incorporated into the system of fig. 1A-3 and may cooperate with the system of fig. 1A-3. Furthermore, at least some portions of the method of fig. 4 may be incorporated into executable instructions stored in non-transitory memory, while other portions of the method may be performed by the controller changing the operating state of the devices and actuators in the physical world.

At 402, method 400 determines a desired transmission gear. In one example, method 400 determines a desired transmission gear in response to vehicle speed and accelerator pedal position or a requested wheel torque determined from accelerator pedal position. Specifically, the method 400 indexes a transmission shift schedule stored in the controller memory. The transmission shift schedule may be a table or function that maintains empirically determined transmission gears. Vehicle speed and accelerator pedal position index the memory locations, and a table or function outputs the desired transmission gear. Method 400 proceeds to 404 after determining the desired transmission gear.

At 404, method 400 judges whether or not a power-on upshift is requested. A power-on upshift is a shift from a lower gear (e.g., gear 1) to a higher gear (e.g., gear 3) when the driver demand torque is greater than zero. The driver required torque is greater than zero when the accelerator pedal is applied or depressed. A power-on upshift may be requested in the event that the desired gear changes from a lower gear to a higher gear (e.g., shifts from gear 2 to gear 3) when the accelerator pedal is applied. If the method 400 concludes that a power-on upshift is requested, the answer is yes and the method 400 proceeds to 406. Otherwise, the answer is no and method 400 proceeds to 440.

At 440, method 400 maintains the current transmission gear or shifts to a desired transmission gear (e.g., downshift). Method 400 shifts according to a shift schedule in response to an accelerator pedal position and a vehicle speed. Alternatively, the method 400 may maintain the currently engaged gear. Method 400 proceeds to exit after shifting or maintaining the transmission gear.

At 406, method 400 judges whether or not the inertia phase of the shift is in progress. The power-on transmission gear upshift consists of two phases. The first phase is a torque phase or torque transfer phase, and the torque phase or torque transfer phase is the time during a shift in which the off-going clutch is being disengaged but is still transferring torque, and the on-coming clutch is being engaged and begins to transfer torque. For the dual clutch transmission shown in FIG. 3, the oncoming clutch may be clutch 126 or clutch 127. The off-going clutch may be clutch 126 or clutch 127. For example, the off-going clutch for a particular shift may be clutch 126 and the on-coming clutch may be clutch 127. The torque transfer phase ends when the torque capacity of the oncoming clutch is zero and the torque capacity of the oncoming clutch is equal to the transmission input torque. The second phase of the transmission shift is the inertia phase and it begins after the torque transfer phase of the shift. In one example, the method 400 may determine that the inertia phase is ongoing in response to the modeled transmission state. If the output from the transmission model indicates that the transmission shift is in the inertia phase, the answer is yes and method 400 proceeds to 408. Otherwise, the answer is no and method 400 proceeds to 450.

At 450, method 400 adjusts the force applied to the off-going clutch and the force applied to the on-coming clutch during the torque transfer phase of the power-on upshift. The force applied to the off-going clutch controls the torque transfer capacity (e.g., the amount of torque that can be transferred from the input side of the clutch, such as the engine side of the clutch, to the output side of the clutch, such as the gearbox side of the clutch). Similarly, the force applied to the oncoming clutch controls the torque transfer capacity of the oncoming clutch. In one example, the method 400 determines and commands an oncoming clutch torque capacity by the following equation:

wherein Tq _{on_clth_cap} Is the torque capacity, RT, of the oncoming clutch _{gear_old} Is the torque ratio of the transmission operating in a disengaged gear (e.g., the old gear) (e.g., the output torque of the transmission divided by the transmission when the old gear is engaged)Input torque of transmission), RT _{gear_new} Is the torque ratio of the transmission operating with the engaged gear (e.g., new gear), tq _{Trn_wo_mod} Is the uncorrected transmission input torque, T is the amount of time elapsed since the torque transfer phase of the current shift, T _{ttp_dur} Is the desired duration of the torque transfer phase of the current shift. Oncoming clutch is commanded to Tq _{on_clth_cap} The value of (c). However, if driveline torque correction is performed during the torque transfer phase by the rear wheel drive motor instead of the engine and integrated starter/generator to fill the potential torque hole, the clutch torque capacity will have a different final torque capacity. The final clutch torque capacity at the end of the torque transfer phase may be the uncorrected transmission input torque. Thus, when the rear wheel drive electric machine provides compensation during the torque phase of a power-on upshift, the oncoming clutch torque capacity may be described by the following equation:

wherein Tq _{Trn_est} Is the estimated transmission input torque. The difference between the torque capacity of the oncoming clutch and the requested maximum instantaneous input torque of the transmission can be used to determine how quickly the transmission gear ratio changes according to the following equation:

wherein Tq _{Trn_inst_max} Is the transmission input maximum instantaneous torque limit, J _{Trn_in} Is the effective input inertia of the variator, omega _{Trn_out} Is the angular speed of the output shaft of the transmission, tq _{on_clth_cap} Is the torque capacity, RT, of the oncoming clutch _{gear_new} Is the torque ratio, RT, of the transmission operating under the new gear _{gear_old} Is the torque ratio of the transmission operating under the old gear, and T _{shft_dur} Is the continuation of a shift or gear ratio changeTime. The transmission input maximum instantaneous torque limit may alternatively be referred to as a transmission input upper limit instantaneous torque threshold, and the transmission input maximum instantaneous torque limit is the transmission input torque that is not exceeded.

A transmission input minimum instantaneous torque limit may be determined to limit transmission input torque through the engine and/or the integrated starter/generator. In one example, the transmission input minimum instantaneous torque limit is determined by the following equation:

wherein Tq _{Trn_min_inst} Is the Transmission input instantaneous minimum Torque Limit, RT _{gear_old} Is the transmission torque ratio at which the old gear is engaged, RT _{gear_new} Is the transmission torque ratio at which new gear is engaged, tq _{Trn_wo_mod} Is uncorrected transmission input torque, and Tq _{on_cltch_cap} Is the torque capacity of the oncoming clutch. Second term of the above formula (e.g.

) Is the torque applied to fill the potential torque hole during the torque transfer phase of the shift. The transmission input minimum instantaneous torque limit can alternatively be referred to as a transmission input lower limit instantaneous torque threshold, and the transmission input minimum instantaneous torque limit is a torque that is less than the transmission input torque. In response to the gear engaging the power-on upshift, the off-going clutch may be released at a predetermined rate. Method 400 proceeds to exit the torque transmitting portion where the transmission shift is performed.

At 408, method 400 retrieves the transmission control variable from memory. In one example, the transmission controller may invoke the control variable from the engine controller via a vehicle system controller and a CAN bus. Specifically, the method 400 recalls from memory the uncorrected transmission input torque, the estimated transmission input torque, and the equivalent transmission input torque. The method 400 proceeds to 410.

At 410, method 400 determines a duration of the desired gear ratio change. The duration of the desired gear ratio change or the amount of time that the shift occurs may be stored in memory. The desired gear ratio change duration value stored in memory may be empirically determined and stored in a table or function that may be indexed by driver requested wheel torque and gear included in the shift. The duration of the desired gear ratio change may be determined by the transmission controller. Method 400 proceeds to 412 after determining the duration of the desired gear ratio change.

At 412, method 400 determines a transmission maximum instantaneous upper torque threshold or limit that is not exceeded. The transmission input instantaneous upper limit torque threshold may also be referred to as a transmission input maximum instantaneous torque limit. In one example, method 400 determines the transmission input maximum instantaneous torque limit from the following equation:

wherein Tq _{Trn_max_inst} Is the transmission input instantaneous maximum torque limit, RT _rep Is a recorded torque ratio, RT, determined by the ratio of transmission input speed to transmission output speed _{gear_new} Is the torque ratio of the new gear, tq _{Trn_wo_mod} Is uncorrected transmission input torque, J _Tm Is the effective inertia of the variator input, ω _Tn Is the variator output angular velocity, RT _{gear_old} Is the torque ratio of the old gear, and T _{shft_dur} Is the duration of the gear ratio change. J is a unit of _Tm The value of (d) may be determined empirically and stored in the controller memory. Likewise, the new gear torque ratios and the old gear torque ratios may be stored in the controller memory. Omega can be determined by means of a rotational speed sensor _Tn And Tq is determined at step 424 _{Trn_wo_mod} . The transmission maximum instantaneous upper limit torque threshold may be determined by a transmission controller. The recorded torque ratio may be determined as described in fig. 10-12. The method 400 proceeds to 414.

At 414, method 400 determines transmission hardware upper torque thresholds or limits that are not exceeded. The transmission hardware upper limit torque threshold or limit may also be referred to as a transmission maximum hardware torque limit. In one example, the method 400 determines the transmission hardware upper torque threshold based on one or more functions that maintain the value of the empirically determined transmission hardware upper torque threshold. The function may have as inputs transmission variables including clutch temperature, transmission oil temperature, and other transmission operating conditions. The outputs of the functions may be summed to provide an estimate of the upper torque threshold of the transmission hardware. The transmission hardware upper torque threshold may be determined by a transmission controller. The method 400 proceeds to 416.

At 416, method 400 determines and commands a desired on-coming clutch torque capacity. In one example, method 400 determines the torque capacity of the oncoming clutch by:

wherein Tq _{on_cltch_cap} Is the torque capacity, RT, of the oncoming clutch _reported Is the recorded transmission torque ratio, RT, as determined by the method of FIG. 10 _{gear_new} Is the transmission torque ratio at which the transmission engages a new gear, tq _{Trn_wo_mod} Is the uncorrected transmission input torque, tq _{Trn_est} Is an estimated transmission input torque, and Tq _{Trn_eqv} Is the transmission equivalent input torque. Torque capacity of the oncoming clutch is commanded to Tq _{on_cltch_cap} The value of (c). The oncoming clutch torque capacity may be determined by the transmission controller. The method 400 proceeds to 418.

At 418, the method 400 stores the transmission instantaneous upper torque threshold and the transmission hardware upper torque threshold to memory. The threshold is stored to memory for later use or for use by an engine or vehicle system controller. The method 400 proceeds to 420.

At 420, method 400 retrieves the transmission instantaneous upper torque threshold and the transmission hardware upper torque threshold from memory. The engine controller or vehicle system controller may invoke the value of the threshold. The method 400 proceeds to 422.

At 422, method 400 determines the transmission input torque without drive correction. As previously mentioned, the vehicle system controller may receive various inputs for requesting braking torque and torque to accelerate the vehicle. For example, the torque to accelerate the vehicle may be input through an accelerator pedal or through an interface with the autonomous driver. In one example, the torque to accelerate the vehicle is a wheel torque determined by the vehicle speed and the accelerator pedal position or voltage. Specifically, vehicle speed and accelerator pedal position are input to a table or function, and the table or function outputs driver demanded wheel torque from a plurality of empirically determined values stored in the table or function. The wheel torque may then be divided or divided into a driver demanded engine torque, a driver demanded integrated starter/generator torque (if present), and a driver demanded rear wheel drive motor torque. The driver requested engine torque, the driver requested integrated starter/generator torque, and the driver requested rear wheel drive motor torque may be divided in response to battery state of charge, integrated starter/generator temperature, rear wheel drive motor temperature, and other vehicle conditions. The driver demanded engine torque adjusted for the transmission gear ratio and the rear wheel drive gear ratio, plus the driver demanded integrated starter/generator torque adjusted for the transmission gear ratio and the rear wheel drive gear ratio, plus the driver demanded rear wheel drive electric machine torque adjusted for the rear wheel drive gear ratio or any other torque of the motor disposed downstream of the transmission or connected to the independent drive shaft, sum to the driver demanded wheel torque at which the transmission engages the gear. The driver demanded wheel torque can be characterized by the following equation:

DD _wheel ＝(DD _eng ·GR _Trn ·GR _FD )+DD _isg ·GR _Trn ·GR _FD +DD _Rdu ·GR _Rdu

wherein DD _wheel Is the driver's demanded wheel torque, DD, as determined by the accelerator pedal position _eng Is driver demanded engine torque, GR _Trn Is the currently engaged transmission gear ratio, GR _FD Is the final drive gear ratio (e.g., transaxle reduction ratio), GR _Rdu Is the gear ratio of the rear wheel drive, DD _isg Is driver demand integrated starter/generator torque, and DD _Rdu Is the driver demanded torque of the rear wheel drive unit. The sum of the driver demanded engine torque and the driver demanded integrated starter/generator torque is the unmodified transmission input torque. In one example, an engine controller determines an uncorrected transmission input torque. Method 400 proceeds to 424 after determining the uncorrected transmission input torque.

At 424, method 400 estimates transmission input torque. For transmission clutch slip, transient transmission torque limits, transmission hardware torque limits, and other transmission conditions, driver demand engine torque and/or integrated starter/generator torque (if present) may be modified so that desired wheel torque may be provided. For example, if the transmission clutch has a low torque capacity in response to the force applied to the clutch, the engine torque may be temporarily reduced to reduce the likelihood of clutch degradation. The engine torque plus the integrated starter/generator torque during these conditions may be referred to as the torque corrected transmission input torque. In one example, the transmission input torque may be described by the following equation:

Tq _{Trn_est} ＝Tq _{isg_est} +Tq _{eng_est}

wherein Tq _{Trn_est} Is an estimated input torque, tq, of the transmission at an input shaft upstream of a transmission clutch _{isg_est} Is the estimated ISG torque, and Tq _{eng_est} Is the estimated engine torque. The method 400 proceeds to 426 after determining the estimated transmission input torque.

At 426, method 400 estimates the equivalent transmission input torque. In one example, the equivalent transmission input torque may be determined by the following equation:

wherein Tq _{Trn_equ} Is the equivalent transmission input torque, tq _{Trn_est} Is an estimated transmission input torque, and Tq _{Rdu_est} Is the estimated rear wheel drive torque. It should be noted that the torque ratios and motors disposed directly behind the transmission or on separate drive shafts may be substituted for the rear wheel drive. Method 400 proceeds to 428 after estimating the equivalent transmission input torque.

At 428, method 400 estimates a percentage of requested driveline torque reduction provided by the engine, the integrated starter/generator, the rear wheel drive electric machine, and/or a motor disposed directly downstream of the transmission or on an independent drive shaft. The method 400 also determines an engine torque reduction threshold and a battery power limit. In one example, method 400 includes an arbiter function that selects a percentage of inertia torque compensated by the engine, the integrated starter/generator, and the rear wheel drive motor. The arbiter allocates a percentage of the inertia torque compensated by the engine, the integrated starter/generator, and the rear wheel drive motor. For example, the engine may be assigned a 20% reduction in inertia torque, the integrated starter/generator may be assigned a 5% reduction in inertia torque, and the rear wheel drive motor may be assigned a 75% reduction in inertia torque. The arbiter may determine the respective inertia torque reduction percentage in response to the optimal fuel economy mode, the optimal driveability mode, and the optimal durability mode. In one example, a table of empirically determined rear wheel drive torque reduction values is stored in the controller memory. The table may be indexed by driver demanded torque, battery power limit, rear wheel drive motor threshold, and vehicle driving mode. The table outputs a percentage value of the compensated torque provided by the rear wheel drive motor. Similar tables may be provided for the engine and the integrated starter/generator. The method 400 proceeds to 430.

At 430, method 400 commands the engine, rear wheel drive motor, and integrated starter/generator. The engine, rear wheel drive motor, and integrated starter/generator are commanded to provide driver demanded wheel torque and inertia torque compensation. The combined engine, integrated starter/generator, and rear wheel drive motor may be commanded to Tq _{Trn_max_inst} Or a lower torque value including inertia torque compensation. Method 400 proceeds to exit.

Referring now to FIG. 5, a prophetic example of a power-on upshift with torque reduction during the inertia phase of the electric motor of the rear wheel drive is shown. The shift schedule shown in FIG. 5 may be provided by the method of FIG. 4 in combination with the system shown in FIGS. 1A-3. The graphs shown in fig. 5 occur simultaneously and are aligned in time. Engine torque compensation for inertia torque during a shift is not provided in the timing sequence of fig. 5.

The first plot from the top of fig. 5 is a plot of engine speed versus time. The vertical axis represents engine speed, and engine speed increases in the direction of the vertical axis arrow. The horizontal axis represents time, and time increases from the left side of the graph to the right side of the graph. Solid line 502 represents engine speed.

The second plot from the top of fig. 5 is a plot of various transmission torque parameters versus time. The vertical axis represents torque, and the torque increases in the direction of the upper arrow along the vertical axis. The torque below the horizontal axis is a negative torque, and the magnitude of the negative torque increases in the direction of the downward arrow along the vertical axis. The horizontal axis represents time, and time increases from the left side of the graph to the right side of the graph. The dotted line 504 represents the transmission maximum instantaneous torque limit or instantaneous transmission input torque upper threshold that is not exceeded. Dashed line 506 represents a transmission maximum hardware torque limit or transmission hardware threshold that is not exceeded. Solid line 508 represents driver demand torque (e.g., torque requested by a person or autonomous vehicle driver). The short dashed line 510 represents transmission input torque. The alternate long and two short dashes lines 512 represent the equivalent transmission input torque (e.g., engine torque and integrated starter/generator torque plus rear wheel drive motor compensation torque). The double dotted line 514 represents a transmission minimum instantaneous input torque limit or transmission input lower torque threshold that is not less than the transmission minimum instantaneous input torque limit or transmission input lower torque threshold. The dash-double-dashed line 516 represents the rear wheel drive motor torque reflected or observed at the transmission input (e.g., clutch housing 393 shown in fig. 3).

The third plot from the top of fig. 5 is a plot of various additional transmission torque parameters versus time. The vertical axis represents torque, and the torque increases in the direction of the upper arrow along the vertical axis. The torque below the horizontal axis is a negative torque, and the magnitude of the negative torque increases in the direction of the downward arrow along the vertical axis. The horizontal axis represents time, and time increases from the left side of the graph to the right side of the graph. The dotted line 520 represents the torque capacity of a second input clutch (e.g., 127 of fig. 3) of the transmission. The solid line 522 represents the torque capacity of the first input clutch (e.g., 126 of FIG. 3) of the transmission. Solid line 524 represents the transmission input torque without torque correction (e.g., an adjusted transmission input torque including a transmission torque threshold and clutch slip). Dashed line 510 represents transmission input torque. The two-dot chain line 512 represents the equivalent transmission input torque.

The fourth plot from the top of fig. 5 is a plot of transmission torque ratio versus time. The vertical axis represents transmission torque ratio, and the transmission torque ratio increases in the direction of the vertical axis arrow. The horizontal axis represents time, and time increases from the left side of the graph to the right side of the graph. Solid line 530 represents the actual transmission torque ratio (e.g., the ratio of transmission input torque to transmission output torque). Dashed line 532 represents a recorded transmission torque ratio (e.g., a ratio of transmission input torque to transmission output torque as determined by transmission input speed and transmission output speed). When only solid line 530 is visible, solid line 530 and dashed line 532 are of equal value.

Unless otherwise noted, the horizontal axis of each graph corresponds to a zero value on the vertical axis. Further, the vertical axis of each graph corresponds to the value of the zero point time. In addition, torque values above the horizontal axis increase positive torque.

At time T0, the engine speed increases, and the driver required torque is an intermediate level. The transmission input torque 510 and the equivalent transmission input torque 512 are substantially equal to (e.g., within 3% of each other) the driver requested torque. The driver demanded torque trace 508, the transmission input torque trace 510, and the equivalent transmission input torque trace 512 are shown slightly separated to improve trace visibility. The torque capacity of the first input clutch of the transmission is at a higher level and the unmodified transmission input torque is at a higher level. The torque capacity of the second input clutch of the transmission is zero. The transmission torque ratio is a higher value indicating that a lower gear (e.g., first gear) providing a higher torque ratio is engaged.

At time T1, a power-on upshift begins and the transmission shifts into a torque transfer phase. The torque capacity 522 of the first input clutch (e.g., the off-going clutch) of the transmission begins to decrease. Shortly thereafter, the transmission minimum instantaneous input torque limit 514 increases. The transmission input torque 510 and the equivalent transmission torque 512 increase to comply with the transmission minimum instantaneous input torque limit. The driver demand torque continues on its current trajectory.

Between time T1 and time T2, the torque capacity 520 of the second input clutch (e.g., the oncoming clutch) of the transmission begins to increase shortly after the torque capacity 522 of the first input clutch of the transmission begins to decrease. The actual transmission torque ratio 530 begins to decrease and the recorded transmission torque ratio 532 remains unchanged. The torque capacity 522 of the first input clutch of the transmission continues to decrease as the first input clutch is disengaged. The torque capacity 520 of the second input clutch of the transmission continues to increase as the second input clutch is engaged. The engine speed 502 continues to increase and the transmission minimum torque limit 514 decreases shortly before time T2.

At time T2, the torque transfer phase of the power-on upshift ends, and the inertia phase of the power-on upshift begins. The torque transfer phase ends when the torque capacity of the first input clutch of the transmission is zero or substantially zero (e.g., less than 5 Nm). Shortly after the inertia phase begins, the torque capacity 520 of the second input clutch of the transmission is increased, and then the transmission maximum instantaneous torque limit 504 is decreased to counteract the inertia torque added to the system. The transmission hardware torque limit 506 is also reduced to protect the transmission components. The magnitude of the negative torque produced by the torque 516 of the rear wheel drive is increased to offset the inertia torque added to the system. In this manner, transmission output torque is maintained to exhibit consistent vehicle acceleration while implementing the desired gear ratio change profile. The transmission input torque 510 is reduced to the level of the driver demanded torque 508 and the equivalent transmission input torque 512 is reduced to the level of the transmission maximum instantaneous torque limit 504 (small gaps between traces are used to improve observability). After entering the inertia phase of the transmission shift, the driver demand torque begins to increase.

Between time T2 and time T3, the rear wheel drive torque reflected at the transmission input decreases to compensate for the torque added to the system during the inertia phase of the transmission shift, and then it increases near the end of the inertia phase of the transmission shift. The amount of rear wheel drive torque reflected at the transmission input shaft is maintained at a relatively large level and then it decreases around time T3. The engine speed 502 decreases toward the transmission input clutch housing speed (not shown). The transmission maximum instantaneous torque limit 504 decreases and then increases near time T3. Similarly, the transmission maximum hardware torque limit 506 decreases, and then increases near time T3. The driver demand torque 508 and the transmission input torque 510 increase. The equivalent transmission input torque 512 decreases and then increases near time T3. The second clutch torque capacity 520 of the transmission is reduced after it is increased. The registered transmission torque ratio 532 is reduced to the level of the actual transmission torque ratio 530.

At time T3, the shift is complete and the engine speed continues to accelerate. The driver demand torque 508, the transmission input torque 510, and the equivalent transmission torque 512 are substantially the same. The rear wheel drive motor torque 516 reflected to the transmission input is zero.

In this way, the inertia torque during the inertia phase of a power-on upshift can be compensated by the rear wheel drive motor torque. By compensating for the inertia torque, driveline torque disturbances may be reduced. Furthermore, rear wheel drive motor torque may maintain smooth vehicle acceleration during gear shifts.

Referring now to FIG. 6, a prophetic example of a power-on upshift with input actuator (e.g., engine and/or integrated starter/generator) torque compensation is shown. The shift schedule shown in FIG. 6 may be provided by the method of FIG. 4 in combination with the system shown in FIGS. 1A-3. The graphs shown in fig. 6 occur simultaneously and are aligned in time. In addition, the shift sequence of fig. 6 is executed at the same vehicle speed and driver demand torque as the shift shown in fig. 5. Further, the gear ratio variation in fig. 6 is the same as that in fig. 5.

The first plot from the top of fig. 6 is a plot of engine speed versus time. The vertical axis represents engine speed, and engine speed increases in the direction of the vertical axis arrow. The horizontal axis represents time, and time increases from the left side of the graph to the right side of the graph. Solid line 602 represents engine speed.

The second plot from the top of fig. 6 is a plot of various transmission torque parameters versus time. The vertical axis represents torque, and the torque increases in the direction of the upper arrow along the vertical axis. The torque below the horizontal axis is a negative torque, and the magnitude of the negative torque increases in the direction of the downward arrow along the vertical axis. The horizontal axis represents time, and time increases from the left side of the graph to the right side of the graph. The dotted line 604 represents the transmission maximum instantaneous torque limit or instantaneous transmission input torque upper threshold that is not exceeded. Dashed line 606 represents a transmission maximum hardware torque limit or transmission hardware threshold that is not exceeded. Solid line 608 represents driver demand torque (e.g., torque requested by a person or autonomous vehicle driver). Dashed line 610 represents transmission input torque. The alternate long and two short dashes line 612 represents the equivalent transmission input torque (e.g., engine torque and integrated starter/generator torque plus rear wheel drive motor compensation torque). The dashed double-dotted line 614 represents a transmission minimum instantaneous input torque limit or a transmission input lower torque threshold, which is not less than the transmission minimum instantaneous input torque limit or the transmission input lower torque threshold. The dash-double dashed line 616 represents rear wheel drive motor torque reflected or observed at the transmission input (e.g., clutch housing 393 shown in fig. 3).

The third plot from the top of fig. 6 is a plot of various additional transmission torque parameters versus time. The vertical axis represents torque, and the torque increases in the direction of the upper arrow along the vertical axis. The torque below the horizontal axis is a negative torque, and the magnitude of the negative torque increases in the direction of the downward arrow along the vertical axis. The horizontal axis represents time, and time increases from the left side of the graph to the right side of the graph. The dotted line 620 represents the torque capacity of a second input clutch of the transmission (e.g., 127 of fig. 3). The solid line 622 represents the torque capacity of the first input clutch (e.g., 126 of FIG. 3) of the transmission. Solid line 624 represents the transmission input torque without torque correction (e.g., the adjusted transmission input torque including the transmission torque threshold and clutch slip). Dashed line 610 represents transmission input torque. The two-dot chain line 612 represents the equivalent transmission input torque.

The fourth plot from the top of fig. 6 is a plot of transmission torque ratio versus time. The vertical axis represents transmission torque ratio, and the transmission torque ratio increases in the direction of the vertical axis arrow. The horizontal axis represents time, and time increases from the left side of the graph to the right side of the graph. Solid line 630 represents the actual transmission torque ratio (e.g., the ratio of transmission input torque to transmission output torque). Dashed line 632 represents a recorded transmission torque ratio (e.g., a ratio of transmission input torque to transmission output torque as determined by transmission input speed and transmission output speed). When only the solid line 630 is visible, the solid line 630 and the dashed line 632 are of equal value.

Unless otherwise noted, the horizontal axis of each graph corresponds to a zero value on the vertical axis. Further, the vertical axis of each graph corresponds to the value of the zero point time.

At time T10, the engine speed 602 increases, and the driver demand torque 608 is at an intermediate level. The transmission input torque 610 and the equivalent transmission input torque 612 are substantially equal to (e.g., within 3% of each other) the driver demand torque 608. The driver demand torque trace 608, the transmission input torque trace 610, and the equivalent transmission input torque trace 612 are shown slightly separated to improve trace visibility. The torque capacity 622 of the first input clutch of the transmission is at a higher level and the uncorrected transmission input torque 624 is at a higher level. The torque capacity 620 of the second input clutch of the transmission is zero. The transmission torque ratio 630 is a higher value indicating that a lower gear (e.g., first gear) providing a higher torque ratio is engaged.

At time T11, a power-on upshift begins and the transmission shifts into a torque transfer phase. The torque capacity 622 of the first input clutch (e.g., the off-going clutch) of the transmission begins to decrease. Shortly thereafter, the transmission minimum instantaneous input torque limit 614 increases. The transmission input torque 610 and the equivalent transmission torque 612 increase to comply with the transmission minimum instantaneous input torque limit 614. The driver demand torque 608 continues on its current trajectory.

Between time T11 and time T12, the torque capacity 620 of the second input clutch of the transmission (e.g., the oncoming clutch) begins to increase shortly after the torque capacity 622 of the first input clutch of the transmission begins to decrease. The actual torque ratio 630 of the transmission begins to decrease and the recorded transmission torque ratio remains unchanged. The torque capacity 622 of the first input clutch of the transmission continues to decrease as the first input clutch is disengaged. The torque capacity 620 of the second input clutch of the transmission continues to increase as the second input clutch is engaged. The engine speed 602 continues to increase and the transmission minimum torque limit is reduced shortly before time T12.

At time T12, the torque transfer phase of the power-on upshift ends and the inertia phase of the power-on upshift begins. The torque transfer phase ends when the torque capacity of the first input clutch of the transmission is zero or substantially zero (e.g., less than 5 Nm). Shortly after the inertia phase begins, the torque capacity 620 of the second input clutch of the transmission is reduced, and then the transmission maximum instantaneous torque limit 604 is reduced to offset the inertia torque added to the system. The transmission hardware torque limit 606 is also reduced to protect the transmission components. Since these limits are equal, the requested torque reduction must be achieved through the transmission component input actuators (engine and/or ISG). The input torque 610 to the transmission input (e.g., clutch housing 393) is reduced via reduction of engine torque by retarding spark and/or reducing engine air flow to offset the inertia torque added to the system. The rear wheel drive motor torque 616 reflected to the transmission input is zero. In this way, the transmission output torque is maintained to exhibit consistent vehicle acceleration while executing the desired gear ratio profile. The transmission input torque and the transmission equivalent input torque are reduced to the level of the transmission maximum instantaneous torque limit (small gaps between traces are used to improve observability). After entering the inertia phase of the transmission shift, the driver demand torque begins to increase. The transmission clutch torque capacity and rear wheel drive torque determine the torque generated at the wheels of the vehicle. The capacity of the transmission clutch is determined to provide constant vehicle acceleration through the rear wheel drive torque compensating output. The difference between the transmission clutch torque capacity and the transmission input torque determines the rate of change of engine speed.

Between time T12 and time T13, the rear wheel drive torque 616 reflected at the transmission input remains zero so that no rear wheel drive motor torque compensation for the inertia torque is provided. The transmission maximum instantaneous torque limit 604 decreases and then increases near time T13. Similarly, the transmission maximum hardware torque limit 606 decreases and then increases near time T13. The driver demand torque 608 increases and the transmission input shaft torque 610 is at the level of the transmission instantaneous torque limit 604 until just before time T13 when it returns to the driver demand torque (trace interval is provided to increase observability). The equivalent transmission input torque 612 is at the level of the transmission instantaneous torque limit 604 until just before its time T13 of return to the driver demand torque 608. The second clutch torque capacity 620 of the transmission is increased near time T13 and the recorded transmission torque ratio 632 is reduced to the level of the actual transmission torque ratio 630. The uncorrected transmission input torque 624 increases.

At time T13, the shift is complete and the engine speed continues to accelerate. The driver demand torque, transmission input torque, and equivalent transmission torque are substantially the same. The rear wheel drive motor torque reflected to the transmission input is zero.

In this way, the inertia torque during the inertia phase of a power-on upshift may be compensated for by reducing the transmission input torque at the transmission clutch housing. The transmission input torque 610 may be reduced by retarding engine spark timing or reducing engine airflow. By compensating for the inertia torque, driveline torque disturbances may be reduced.

The shift schedule of FIG. 5 may have reduced losses and higher efficiency than the shift schedule of FIG. 6. Further, the profiles of the oncoming clutch are the same in fig. 5 and 6, but the torque transmitted through the oncoming clutch in the timing sequence of fig. 5 is large.

Referring now to fig. 7, a prophetic example of a rear wheel drive motor torque compensated power-on upshift is shown when the rear wheel drive motor is charging the battery or electrical energy storage device. The shift schedule shown in FIG. 7 may be provided by the method of FIG. 4 in combination with the system shown in FIGS. 1A-3. The graphs shown in fig. 7 occur simultaneously and are aligned in time. In addition, the shift sequence of fig. 7 is executed at the same vehicle speed and driver demanded torque as the shift shown in fig. 5, except that the rear wheel drive is charging the vehicle high voltage battery. Further, the gear ratio variation in fig. 7 is the same as that in fig. 5.

In this example, the maximum transmission protection limit is less than the maximum torque coordination limit. The transmission assembly input torque is reduced to a maximum transmission protection limit 704. The rear wheel drive motor fills the torque differential to achieve the desired wheel torque profile and the capacity of the on-coming clutch is reduced to ensure a consistent gear ratio profile.

The first plot from the top of fig. 7 is a plot of engine speed versus time. The vertical axis represents engine speed, and engine speed increases in the direction of the vertical axis arrow. The horizontal axis represents time, and time increases from the left side of the graph to the right side of the graph. Solid line 702 represents engine speed.

The second plot from the top of fig. 7 is a plot of various transmission torque parameters versus time. The vertical axis represents torque, and the torque increases in the direction of the upper arrow along the vertical axis. The torque below the horizontal axis is a negative torque, and the magnitude of the negative torque increases in the direction of the downward arrow along the vertical axis. The horizontal axis represents time, and time increases from the left side of the graph to the right side of the graph. The dotted line 704 represents the transmission maximum instantaneous torque limit or instantaneous transmission input torque upper threshold that is not exceeded. Dashed line 706 represents a transmission maximum hardware torque limit or transmission upper hardware threshold that is not exceeded. Solid line 708 represents driver demand torque (e.g., torque requested by a person or autonomous vehicle driver). Dashed line 710 represents transmission input torque. The two-dot chain line 712 represents the equivalent transmission input torque. The double dotted line 714 represents a transmission minimum instantaneous input torque limit or transmission input lower torque threshold, which is not less than the transmission minimum instantaneous input torque limit or transmission input lower torque threshold. The long dashed double dashed line 716 represents rear wheel drive motor torque reflected or observed at the transmission input (e.g., clutch housing 393 shown in fig. 3).

The third plot from the top of fig. 7 is a plot of various additional transmission torque parameters versus time. The vertical axis represents torque, and torque increases in the direction of the upper arrow along the vertical axis. The torque below the horizontal axis is a negative torque, and the magnitude of the negative torque increases in the direction of the downward arrow along the vertical axis. The horizontal axis represents time, and time increases from the left side of the graph to the right side of the graph. Dotted line 720 represents the torque capacity of a second input clutch (e.g., 127 of fig. 3) of the transmission. The solid line 722 represents the torque capacity of the first input clutch (e.g., 126 of FIG. 3) of the transmission. Solid line 724 represents transmission input torque without torque correction. Dashed line 710 represents transmission input torque. The two-dot chain line 712 represents the equivalent transmission input torque.

The fourth plot from the top of fig. 7 is a plot of transmission torque ratio versus time. The vertical axis represents transmission torque ratio, and the transmission torque ratio increases in the direction of the vertical axis arrow. The horizontal axis represents time, and time increases from the left side of the graph to the right side of the graph. Solid line 730 represents the actual transmission torque ratio (e.g., the ratio of transmission input torque to transmission output torque). Dashed line 732 represents a recorded transmission torque ratio (e.g., a ratio of transmission input torque to transmission output torque as determined by transmission input speed and transmission output speed). When only solid line 730 is visible, solid line 730 and dashed line 732 are of equal value.

At time T20, the engine speed 702 increases and the driver demand torque 708 is at an intermediate level. The transmission input torque 710 and the equivalent transmission input torque 712 are substantially equal, and the driver demand torque 708 is less than the transmission input torque 710 and the equivalent transmission input torque 712. The transmission input torque trace 710 and the equivalent transmission input torque trace 712 are shown slightly separated to improve curve visibility. The driver demand torque 708 is less than the transmission input torque 710 because engine torque is input to the transmission and converted to electrical energy at the rear wheel drive electric machines. The difference between the transmission input torque 710 and the driver demand torque 708 is the engine torque converted to an electrical charge. The torque capacity 722 of the first input clutch of the transmission is at a higher level and the unmodified transmission input torque 724 is at a higher level. The torque capacity 720 of the second input clutch of the transmission is zero. The transmission torque ratio 730 is a higher value indicating that a lower gear (e.g., first gear) that provides a higher torque ratio is engaged.

At time T21, a power-on upshift begins and the transmission shifts into a torque transfer phase. The torque capacity 722 of the first input clutch (e.g., the off-going clutch) of the transmission begins to decrease. Shortly thereafter, the transmission minimum instantaneous input torque limit 714 is increased. The transmission input torque 710 and the equivalent transmission torque 712 increase to comply with the transmission minimum instantaneous input torque limit 714. The driver demand torque 708 continues on its current trajectory.

Between time T21 and time T22, the torque capacity 720 of the second input clutch of the transmission (e.g., the oncoming clutch) begins to increase shortly after the torque capacity 722 of the first input clutch of the transmission begins to decrease. The actual transmission torque ratio 730 begins to decrease and the recorded transmission torque ratio 732 remains unchanged. The torque capacity 722 of the first input clutch of the transmission continues to decrease as the first input clutch is disengaged. The torque capacity 720 of the second input clutch of the transmission continues to increase as the second input clutch is engaged. The engine speed 702 continues to increase and the transmission minimum torque limit 714 is reduced shortly before time T22.

At time T22, the torque transfer phase of the power-on upshift ends and the inertia phase of the power-on upshift begins. The torque transfer phase ends when the torque capacity of the first input clutch of the transmission is zero or substantially zero (e.g., less than 5 Nm). Shortly after the inertia phase begins, the torque capacity of the second input clutch of the transmission is reduced, and then the transmission maximum instantaneous torque limit 704 is reduced to offset the inertia torque added to the system. The transmission hardware torque limit 706 is also reduced to protect the transmission components and has a value less than the maximum instantaneous torque limit 704. The input torque to the transmission input is reduced 710 via reduction of engine torque by retarding spark and/or reducing engine air flow to counteract the inertia torque added to the system. The magnitude of the rear wheel drive motor torque 716 reflected to the transmission input is reduced from a larger charging torque to a smaller charging torque. In this way, the reduction in engine torque may not be observed at the vehicle wheels as the rear wheel drive motor charge torque is reduced, thereby offsetting the reduction in engine torque. The reduction in rear wheel drive motor charge torque 716 reduces the negative torque applied to the driveline. In this way, vehicle acceleration may be maintained. The transmission input torque 710 is reduced to a level below the transmission maximum instantaneous torque limit 704 and the transmission equivalent input torque 712 is reduced to the level of the transmission maximum instantaneous torque limit 704 (small gaps between traces are used to improve observability). After entering the inertia phase of the transmission shift, the driver demand torque 708 begins to increase.

Between time T22 and time T23, the rear wheel drive torque 716 reflected at the transmission is reduced to a lower charging torque, such that the rear wheel drive motor torque compensation for the inertia torque causes the equivalent transmission input torque 712 to equal the transmission maximum instantaneous torque limit 704. The transmission maximum instantaneous torque limit 704 decreases and then increases near time T23. Similarly, the transmission maximum hardware torque limit 706 decreases and then increases near time T23. The driver demand torque 708 increases and the transmission input shaft torque 710 is at the level of the transmission maximum hardware torque limit 706 until just before time T23 when it returns to a level equal to the driver demand torque 708 plus the battery charge torque. The equivalent transmission input torque 712 is at the level of the transmission instantaneous torque limit 704 until just before its time T23 of return to the driver demanded torque 708 plus the charging torque. The second clutch torque capacity 720 of the transmission is increased near time T23 and the recorded transmission torque ratio 732 is reduced to the level of the actual transmission torque ratio 730. The uncorrected transmission input torque 724 increases.

At time T23, the shift is complete and the engine speed continues to accelerate. The transmission input torque 710 and the equivalent transmission torque 712 are substantially the same. The rear wheel drive motor torque 716 reflected to the transmission input is reduced to its value prior to transmission shifting, which is equal to the charging torque.

In this way, the inertia torque during the inertia phase of a power-on upshift may be compensated for by reducing the transmission input torque at the transmission clutch housing. The transmission input torque may be reduced by reducing the rear wheel drive electric machine charging torque. By compensating for the inertia torque, driveline torque disturbances may be reduced.

Referring now to fig. 8, a prophetic example of a rear wheel drive motor torque compensated power-on upshift is shown when the rear wheel drive motor is charging the battery or electrical energy storage device. The shift schedule shown in FIG. 8 may be provided by the method of FIG. 4 in combination with the system shown in FIGS. 1A-3. The graphs shown in fig. 8 occur simultaneously and are aligned in time. In addition, the shift sequence of fig. 8 is executed at the same vehicle speed and driver demand torque as the shift shown in fig. 5. Further, the gear ratio variation in fig. 8 is the same as that in fig. 5.

In some conditions, the rear wheel drive electric machine may not be able to provide transmission torque correction. The desired torque may be delivered by reducing the duration of the desired gear ratio change whenever the equivalent transmission component input torque differs from the maximum transmission torque coordination limit. The timing diagram of fig. 8 shows an example where the motor is unable to provide torque correction. The timing sequence of fig. 8 is the same as that shown in fig. 7, but the rear wheel drive motor torque remains constant during the shift. The transmission controller performs a gear ratio change in a short amount of time, but the actual wheel torque profile is the same between the two cases.

The first plot from the top of fig. 8 is a plot of engine speed versus time. The vertical axis represents engine speed, and engine speed increases in the direction of the vertical axis arrow. The horizontal axis represents time, and time increases from the left side of the graph to the right side of the graph. Solid line 802 represents engine speed.

The second plot from the top of fig. 8 is a plot of various transmission torque parameters versus time. The vertical axis represents torque, and the torque increases in the direction of the upper arrow along the vertical axis. The torque below the horizontal axis is a negative torque, and the magnitude of the negative torque increases in the direction of the downward arrow along the vertical axis. The horizontal axis represents time, and time increases from the left side of the graph to the right side of the graph. The dotted line 804 represents the transmission maximum instantaneous torque limit or instantaneous transmission input torque upper threshold that is not exceeded. Dashed line 806 represents a transmission maximum hardware torque limit or transmission hardware upper threshold that is not exceeded. Solid line 808 represents driver demand torque (e.g., torque requested by a person or autonomous vehicle driver). Dashed line 810 represents transmission input torque. The two-dot chain line 812 represents the equivalent transmission input torque. The double dotted line 814 represents a transmission minimum instantaneous input torque limit or transmission input lower torque threshold that is not less than the transmission minimum instantaneous input torque limit or transmission input lower torque threshold. The long dash-double dashed line 816 represents rear wheel drive motor torque reflected or observed at the transmission input.

The third plot from the top of fig. 8 is a plot of various additional transmission torque parameters versus time. The vertical axis represents torque, and torque increases in the direction of the upper arrow along the vertical axis. The torque below the horizontal axis is a negative torque, and the magnitude of the negative torque increases in the direction of the downward arrow along the vertical axis. The horizontal axis represents time, and time increases from the left side of the graph to the right side of the graph. The dotted line 820 represents the torque capacity of a second input clutch of the transmission (e.g., 127 of fig. 3). Solid line 822 represents the torque capacity of the first input clutch of the transmission (e.g., 126 of fig. 3). Solid line 824 represents transmission input torque without torque correction. Dashed line 810 represents transmission input torque. The two-dot chain line 812 represents the equivalent transmission input torque.

The fourth plot from the top of fig. 8 is a plot of transmission torque ratio versus time. The vertical axis represents transmission torque ratio, and the transmission torque ratio increases in the direction of the vertical axis arrow. The horizontal axis represents time, and time increases from the left side of the graph to the right side of the graph. Solid line 830 represents actual transmission torque ratios (e.g., the ratio of transmission input torque to transmission output torque). Dashed line 832 represents a recorded transmission torque ratio (e.g., a ratio of transmission input torque to transmission output torque as determined by transmission input speed and transmission output speed). When only solid line 830 is visible, solid line 830 and dashed line 832 are of equal value.

At time T30, the engine speed 802 increases, and the driver demand torque 808 is at an intermediate level. The transmission input torque 810 and the equivalent transmission input torque 812 are substantially equal, and the driver demanded torque 808 is less than the transmission input torque 810 and the equivalent transmission input torque 812. The transmission input torque trace 810 and the equivalent transmission input torque trace 812 are shown slightly separated to improve curve visibility. The driver demand torque 808 is less than the transmission input torque 810 because the engine torque is input to the transmission and converted to electrical energy at the rear wheel drive electric machine. The difference between the transmission input torque 810 and the driver demand torque 808 is the engine torque that is converted to an electrical charge. The torque capacity 822 of the first input clutch of the transmission is at a higher level and the uncorrected transmission input torque 824 is at a higher level. The torque capacity 820 of the second input clutch of the transmission is zero. The transmission torque ratio 830 is a higher value indicating that a lower gear (e.g., first gear) providing a higher torque ratio is engaged.

At time T31, a power-on upshift begins and the transmission shifts into a torque transfer phase. The torque capacity 822 of the first input clutch (e.g., the off-going clutch) of the transmission begins to decrease. Shortly thereafter, the transmission minimum instantaneous input torque limit 814 is increased. The transmission input torque 810 and the equivalent transmission torque 812 increase to comply with the transmission minimum instantaneous input torque limit 814. The driver demand torque 808 continues on its current trajectory.

Between time T31 and time T32, the torque capacity 820 of the second input clutch of the transmission (e.g., the oncoming clutch) begins to increase shortly after the torque capacity 822 of the first input clutch of the transmission begins to decrease. The actual transmission torque ratio 830 begins to decrease and the recorded transmission torque ratio 832 remains constant. The torque capacity 822 of the first input clutch of the transmission continues to decrease as the first input clutch is disengaged. The torque capacity 820 of the second input clutch of the transmission continues to increase as the second input clutch is engaged. The engine speed 802 continues to increase and the transmission minimum instantaneous torque limit 814 decreases shortly before time T32.

At time T32, the torque transfer phase of the power-on upshift ends, and the inertia phase of the power-on upshift begins. The torque transfer phase ends when the torque capacity of the first input clutch of the transmission is zero or substantially zero (e.g., less than 5 Nm). Shortly after the inertia phase begins, the torque capacity 820 of the second input clutch of the transmission begins to decrease slightly, and then the transmission maximum instantaneous torque limit 804 decreases to offset the inertia torque added to the system. The transmission hardware torque limit 806 is also reduced to protect the transmission components and has a value less than the maximum instantaneous torque limit 804. The input torque to the transmission input is reduced by reducing the engine torque by retarding spark and/or reducing engine air flow 810 to counteract the inertia torque added to the system. The rear wheel drive motor torque 816 reflected to the transmission input remains constant. In this way, the transmission output torque is maintained to exhibit consistent vehicle acceleration when executing the gear ratio change profile. However, the duration of the gear ratio change phase is shortened. The transmission input torque 810 and the transmission equivalent input torque 812 are reduced to a level less than the transmission maximum instantaneous torque limit 804 (small gaps between traces are used to improve observability). The transmission maximum instantaneous torque limit 804 is reduced to a level greater than the transmission maximum hardware torque limit 806. After entering the inertia phase of the transmission shift, the driver demanded torque 808 begins to increase.

Between time T32 and time T33, the rear wheel drive torque 816 reflected at the transmission remains constant, thereby continuing uninterrupted battery charging. The transmission maximum instantaneous torque limit 804 decreases and then increases near time T33. Similarly, the transmission maximum hardware torque limit 806 decreases and then increases near time T33. The transmission maximum hardware torque limit 806 is reduced to a level less than the transmission instantaneous torque limit 804. The driver demand torque 808 increases and the transmission input shaft torque 810 is at the level of the transmission hardware torque limit 806 until just before time T33 when it returns to a level equal to the driver demand torque 808 plus the battery charge torque. The equivalent transmission input torque 812 is also at the level of the transmission maximum hardware torque limit 806 until just before time T33 when it returns to the driver demanded torque 808 plus the charging torque. The second clutch torque capacity 820 of the transmission is increased near time T33 and the recorded transmission torque ratio 832 is reduced to the level of the actual transmission torque ratio 830. The uncorrected transmission input torque 824 increases.

At time T33, the shift is complete and the engine speed 802 continues to accelerate. The transmission input torque 810 and the equivalent transmission torque 812 are substantially the same. The rear wheel drive motor torque 816, reflected to the transmission input, is reduced to its value prior to transmission shifting, which is equal to the charging torque.

In this way, the inertia torque during the inertia phase of a power-on upshift may be compensated for by reducing the transmission input torque at the transmission clutch housing. The transmission input torque may be reduced by reducing the engine and/or integrated starter/generator torque. By compensating for the inertia torque, driveline torque disturbances may be reduced.

Referring now to fig. 9, a prophetic example of a rear wheel drive motor torque compensated power-on upshift is shown when the rear wheel drive motor is charging the battery or electrical energy storage device. The shift schedule shown in FIG. 9 may be provided by the method of FIG. 4 in combination with the system shown in FIGS. 1A-3. The graphs shown in fig. 9 occur simultaneously and are aligned in time. In addition, the shift schedule of fig. 9 is executed at the same vehicle speed and driver demand torque as the shift shown in fig. 5. Further, the gear ratio variation in fig. 9 is the same as that in fig. 5.

The timing diagram of fig. 9 shows the system response to the same pedal demand shown in fig. 8 when the system is discharged by the rear wheel drive motor (e.g., positive torque is provided to the driveline by the rear wheel drive). The engine may not be able to reduce the transmission input torque to a desired level because the transmission component input torque is low prior to the transmission shift. In this example, the minimum instantaneous torque that can be delivered by reducing the spark is 0Nm. The rear wheel drive motor provides the remainder of the torque reduction during the inertia phase of the transmission shift.

The first plot from the top of fig. 9 is a plot of engine speed versus time. The vertical axis represents engine speed, and engine speed increases in the direction of the vertical axis arrow. The horizontal axis represents time, and time increases from the left side of the graph to the right side of the graph. Solid line 902 represents engine speed.

The second plot from the top of fig. 9 is a plot of various transmission torque parameters versus time. The vertical axis represents torque, and the torque increases in the direction of the upper arrow along the vertical axis. The torque below the horizontal axis is a negative torque, and the magnitude of the negative torque increases in the direction of the downward arrow along the vertical axis. The horizontal axis represents time, and time increases from the left side of the graph to the right side of the graph. The dotted line 904 represents the transmission maximum instantaneous torque limit or instantaneous transmission input torque upper threshold that is not exceeded. Dashed line 906 represents a transmission maximum hardware torque limit or transmission upper hardware threshold that is not exceeded. The solid line 908 represents the driver required torque. Dashed line 910 represents transmission input torque. The two-dot chain line 912 represents the equivalent transmission input torque. The double dotted line 914 represents a transmission minimum instantaneous input torque limit or a transmission input lower torque threshold value that is not less than the transmission minimum instantaneous input torque limit or the transmission input lower torque threshold value. The dash-double dashed line 916 represents rear wheel drive motor torque reflected or observed at the transmission input.

The third plot from the top of fig. 9 is a plot of various additional transmission torque parameters versus time. The vertical axis represents torque, and torque increases in the direction of the upper arrow along the vertical axis. The torque below the horizontal axis is a negative torque, and the magnitude of the negative torque increases in the direction of the downward arrow along the vertical axis. The horizontal axis represents time, and time increases from the left side of the graph to the right side of the graph. Dotted line 920 represents the torque capacity of a second input clutch of the transmission (e.g., 127 of fig. 3). Solid line 922 represents the torque capacity of a first input clutch of the transmission (e.g., 126 of fig. 3). Solid line 924 represents torque-corrected transmission input torque. Dashed line 910 represents transmission input torque. The two-dot chain line 912 represents the equivalent transmission input torque.

The fourth plot from the top of fig. 9 is a plot of transmission torque ratio versus time. The vertical axis represents transmission torque ratio, and the transmission torque ratio increases in the direction of the vertical axis arrow. The horizontal axis represents time, and time increases from the left side of the graph to the right side of the graph. Solid line 930 represents the actual transmission torque ratio (e.g., the ratio of transmission input torque to transmission output torque). Dashed line 932 represents a recorded transmission torque ratio (e.g., a ratio of transmission input torque to transmission output torque as determined by transmission input speed and transmission output speed). When only solid line 830 is visible, solid line 930 and dashed line 932 are of equal value.

At time T40, the engine speed 902 increases and the driver demand torque 908 is at a higher level. The transmission input torque 910 and the equivalent transmission input torque 912 are substantially equal. The transmission input torque trace 910 and the equivalent transmission input torque trace 912 are shown slightly separated to improve curve visibility. The torque capacity 922 of the first input clutch of the transmission is at a higher level and the modified transmission input torque 924 is at a higher level. The torque capacity 920 of the second input clutch of the transmission is zero. The transmission torque ratio 930 is a higher value indicating that a lower gear (e.g., first gear) providing a higher torque ratio is engaged.

At time T41, a power-on upshift begins and the transmission shifts into a torque transfer phase. The torque capacity of the first input clutch (e.g., the off-going clutch) of the transmission begins to decrease. Shortly thereafter, the transmission minimum instantaneous input torque limit 914 is increased. The transmission input torque 910 and the equivalent transmission torque 912 increase to follow the transmission minimum instantaneous input torque limit 914. The driver demand torque 908 continues on its current trajectory.

Between time T41 and time T42, the torque capacity 920 of the second input clutch of the transmission (e.g., the oncoming clutch) begins to increase shortly after the torque capacity 922 of the first input clutch of the transmission begins to decrease. The actual transmission torque ratio 930 begins to decrease and the recorded transmission torque ratio 932 remains constant. The torque capacity 922 of the first input clutch of the transmission continues to decrease as the first input clutch is disengaged. The torque capacity 920 of the second input clutch of the transmission continues to increase as the second input clutch is engaged. The engine speed 902 continues to increase and the transmission minimum instantaneous torque limit 914 is reduced shortly before time T42.

At time T42, the torque transfer phase of the power-on upshift ends, and the inertia phase of the power-on upshift begins. The torque transfer phase ends when the torque capacity of the first input clutch of the transmission is zero or substantially zero (e.g., less than 5 Nm). Shortly after the inertia phase begins, the torque capacity 920 of the second input clutch of the transmission increases and then begins to decrease slightly, and then the transmission maximum instantaneous torque limit 904 decreases to offset the inertia torque added to the system. The transmission hardware torque limit 906 is also reduced but to a lesser amount to protect the transmission components. The input torque to the transmission input is reduced 910 via reducing the engine torque by retarding spark and/or reducing engine air flow to offset the inertia torque added to the system. However, the engine and/or ISG may not be able to provide the full amount of torque reduction. In view of this, the rear wheel drive motor torque reflected to the transmission input is also reduced from a higher positive torque to a lower positive torque. In this way, the amount of reduction in the rear wheel drive motor torque and engine torque can compensate for the amount of increase in the inertia torque. Therefore, the vehicle acceleration can be maintained. The transmission input torque 910 (e.g., engine torque and integrated starter/generator torque) is reduced to zero and the transmission equivalent input torque 912 is reduced to the level of the transmission maximum instantaneous torque limit 904 (small gaps between traces are used to improve observability), both the transmission equivalent input torque 912 and the transmission maximum instantaneous torque limit 904 being less than the transmission maximum hardware torque limit 906. After entering the inertia phase of the transmission shift, the driver demand torque 908 begins to increase.

Between time T42 and time T43, rear wheel drive torque 916, reflected at the transmission, is decreased to compensate for the increase in inertia torque. The transmission maximum instantaneous torque limit 904 decreases and then increases near time T43. Similarly, the transmission maximum hardware torque limit 906 decreases and then increases near time T43. The transmission maximum hardware torque limit 906 is reduced to a level greater than the transmission instantaneous torque limit 904. The driver demand torque 908 increases and the transmission input shaft torque 910 is at a level of zero until just before time T43 when it returns to a level equal to the driver demand torque. The equivalent transmission input torque 912 is also at the level of the transmission maximum instantaneous torque limit 904 until just before its time T43 of return to the driver demanded torque. The second clutch torque capacity 920 of the transmission is increased near time T43 and the recorded transmission torque ratio 932 is reduced to the level of the actual transmission torque ratio 930. The corrected transmission input torque 924 increases.

At time T43, the shift is complete and the engine speed continues to accelerate. The driver demand torque 908 is at a higher level and the transmission input torque 910 and the equivalent transmission torque 912 are substantially the same. The rear wheel drive motor torque 916, reflected to the transmission input, returns to its value prior to the transmission shift, which is equal to the charging torque.

In this way, the inertia torque during the inertia phase of a power-on upshift may be compensated for by reducing the transmission input torque at the transmission clutch housing. The transmission equivalent input torque can be reduced by reducing the rear wheel drive electric machine torque and the engine torque. By compensating for the inertia torque, driveline torque disturbances may be reduced.

Referring now to FIG. 10, a method for determining torque ratios of the transmission is shown. The method of fig. 10 may be incorporated into and cooperate with the systems of fig. 1A-3 and the method of fig. 4. Furthermore, at least some portions of the method of fig. 10 may be incorporated into executable instructions stored in non-transitory memory, while other portions of the method may be performed by the controller changing the operating state of the devices and actuators in the physical world.

At 1002, method 1000 judges whether or not an upshift is requested. An upshift is a transmission shift from a lower gear (e.g., a first gear) to a higher gear (e.g., a second gear). An upshift may be requested when the desired gear changes from a lower gear to a higher gear (e.g., shifts from gear 2 to gear 3) when the vehicle is accelerating or when the shift schedule indicates that a higher vehicle speed for the desired gear is desired. The shift schedule may output a desired transmission gear in response to vehicle speed and accelerator pedal position. The desired gear ratio in the shift schedule may be determined empirically. If method 1000 concludes that an upshift is requested, the answer is yes and method 1000 proceeds to 1004. Otherwise, the answer is no and method 1000 proceeds to 1030.

At 1004, method 100 judges whether or not a torque transmitting phase of transmission shifting is in progress. The transmission gear upshift may consist of two stages. The first phase is a torque phase or torque transfer phase, and the torque phase or torque transfer phase is the time during a shift when the off-going clutch is disengaging but still transferring torque, and the on-coming clutch is engaging and beginning to transfer torque. For the dual clutch transmission shown in FIG. 3, the oncoming clutch may be clutch 126 or clutch 127. The off-going clutch may be clutch 126 or clutch 127. For example, the off-going clutch for a particular shift may be clutch 126 and the on-coming clutch may be clutch 127. The second phase of the transmission shift is the inertia phase, and the inertia phase begins when the off-going clutch stops transmitting torque, while the on-coming clutch continues to engage and transmit torque. The shift is ended when the oncoming clutch is fully engaged and there is substantially zero slip (e.g., the difference in rotational speed from the input side of the clutch to the output side of the clutch is less than 30 RPM). In one example, method 1000 determines whether a torque phase is ongoing in response to a time since the off-going clutch is activated. For example, method 1000 may include empirically determining a torque phase timing value and an inertia phase timing value for each transmission shift (e.g., 1 st gear to 2 nd gear, 2 nd gear to 3 rd gear, etc.). Additionally, the torque phase time and inertia phase time of the shift may be adjusted. If the time from the start of the shift indicates that the transmission shift is in a torque-transmitting phase, the answer is yes and method 1000 proceeds to 1006. Otherwise, the answer is no and method 1000 proceeds to 1016.

At 1006, method 1000 judges whether or not the transmission torque ratio is approximately calculated from the measured transmission input speed and transmission output speed. Method 1000 may conclude that a transmission torque ratio is approximately calculated from a transmission input speed and a transmission output speed during a condition in which a transmission controller controls torque transfer through the transmission. On the other hand, if the vehicle system controller controls the transmission of torque through the transmission, it may be desirable to determine the transmission torque ratio by the torque capacity of the transmission clutch (e.g., the amount of torque that the transmission clutch may transmit from its input to its output). If method 1000 concludes that the transmission controller is adjusting torque flow through the transmission and that the transmission torque ratio is determined by the transmission input speed and the transmission output speed, the answer is yes and method 1000 proceeds to 1008. Otherwise, the answer is no and method 1000 proceeds to 1009.

At 1008, method 1000 determines a torque ratio of the transmission by dividing the transmission output speed by the transmission input speed. The transmission input speed may be determined by an engine speed sensor and the transmission output speed may be determined by a transmission output speed sensor. Method 1000 proceeds to 1010.

At 1010, method 1000 determines a transmission input minimum instantaneous torque limit, which may be referred to as a transmission input instantaneous lower limit torque threshold. The transmission input torque is requested to be greater than or equal to the transmission input minimum instantaneous torque limit. As previously mentioned, the vehicle system controller may receive various inputs for requesting braking torque and torque to accelerate the vehicle. For example, the torque to accelerate the vehicle may be input through an accelerator pedal or through an interface with the autonomous driver. In one example, the torque to accelerate the vehicle is a wheel torque determined by the vehicle speed and the accelerator pedal position or voltage. Specifically, vehicle speed and accelerator pedal position are input to a table or function, and the table or function outputs driver demanded wheel torque from a plurality of empirically determined values stored in the table or function. The wheel torque may then be divided or divided into a driver demanded engine torque, a driver demanded integrated starter/generator torque (if present), and a driver demanded rear wheel drive motor torque. The driver requested engine torque, the driver requested integrated starter/generator torque, and the driver requested rear wheel drive motor torque may be divided in response to a battery state of charge (SOC), an integrated starter/generator temperature, a rear wheel drive motor temperature, and other vehicle conditions.

For example, if the SOC is high and the driver demanded wheel torque is low, the driver demanded engine torque and the driver demanded integrated starter/generator torque may be zero, while the driver demanded rear wheel drive motor torque provides the driver demanded wheel torque. If SOC is low and driver demand is moderate, the driver demanded rear wheel drive motor torque and driver demanded integrated starter/generator torque may be zero, while the driver demanded engine torque provides the driver demanded wheel torque. The driver demanded engine torque for transmission gear ratio and rear wheel drive gear ratio adjustments, plus the driver demanded integrated starter/generator torque for transmission gear ratio and rear wheel drive gear ratio adjustments, plus the driver demanded rear wheel drive electric machine torque for rear wheel drive gear ratio adjustments, sum to the driver demanded wheel torque at the time the transmission engages the gear.

For transmission clutch slip, transient transmission torque limits, transmission hardware torque limits, and other transmission conditions, driver demand engine torque and/or integrated starter/generator torque (if present) may be modified so that desired wheel torque may be provided. For example, if the transmission clutch has a low torque capacity in response to the force applied to the clutch, the engine torque may be temporarily reduced to reduce the likelihood of clutch degradation. The engine torque plus the torque of the integrated starter/generator during these conditions may be referred to as the torque corrected transmission input torque. The total driver-demanded engine torque and driver-demanded integrated starter/generator torque determined from the driver-demanded wheel torque are the uncorrected transmission input torque without correcting transmission clutch slip, transient transmission torque limits, transmission hardware torque limits, and other transmission states, and when the system includes an engine, an integrated starter/generator, and a rear wheel drive electric machine, the uncorrected transmission input torque may be represented by the following equation:

wherein Tq _{Trn_wo_mod} Is the uncorrected transmission input torque, tq _{dd_whl} Is the driver's requested wheel torque, tq, as determined by the accelerator pedal position _Rdu Is the output torque of the motor of the rear wheel drive, gr _Rdu Is the torque ratio of the rear wheel drive，Gr _Trn Is the currently engaged transmission torque ratio, and Tq _Isg Is the torque output by the integrated starter/generator.

In one example, method 1000 determines the transmission input minimum instantaneous torque limit or the transmission input instantaneous lower limit torque threshold by the following equation:

wherein Tq _{Trn_min_inst} For transmission input instantaneous minimum torque limit, RT _{gear_old} Is the transmission torque ratio at the time of engagement of the old gear, RT _{gear_new} Is the transmission torque ratio at the time of engagement of the new gear, tq _{Trn_wo_mod} Is uncorrected transmission input torque, and Tq _{on_cltch_cap} Is the torque capacity of the oncoming clutch. The second term of the above formula (e.g.,

) Is the torque applied to fill the potential torque hole during the torque transfer phase of the shift. The torque capacity of the oncoming clutch may be determined by the following equation:

wherein Tq _{on_clth_cap} Is the torque capacity, RT, of the oncoming clutch _reported Is a recorded transmission torque ratio, RT, as determined by dividing the output speed of the transmission by the input speed of the transmission _{gear_new} Is the torque ratio of the transmission when it engages a new gear, and Tq _{Trn_wo_mod} Is the transmission input torque without correction. The torque capacity of the off-going clutch may follow a predetermined trajectory stored in the controller memory, or it may be a calculated value. Method 1000 proceeds to 1012.

At 1012, method 1000 adjusts the torque capacity of the offgoing clutch and the oncoming clutch offTorque capacity of the clutch. The capacity of the off-going clutch and the capacity of the on-coming clutch are adjusted by commanding clutch actuators 387 and 389. The oncoming clutch is adjusted to Tq _{on_clth_cap} And the off-going clutch is adjusted to the value of the clutch torque capacity trajectory stored in the controller memory. Additionally, method 1000 adjusts engine torque and/or integrated starter/generator torque to transmission input transient lower limit torque threshold Tq _{Trn_min_inst} To fill a torque hole that may be created when the oncoming clutch is released. Method 1000 proceeds to exit.

At 1009, method 1000 estimates transmission input torque. As previously described, transmission input torque may be estimated as Tq in response to accelerator pedal position _{Trn_wo_mod} The value of (c). Method 1000 proceeds to 1011.

At 1011, method 1000 determines and commands the capacity of the oncoming clutch and the off-going clutch. The capacity of the oncoming clutch may be determined by the following equation:

wherein Tq _{on_cltch_cap} Is the oncoming clutch torque capacity, tq _{Trn_wo_mod} Is the uncorrected transmission input torque, T is the elapsed time of the torque transfer phase of the current transmission shift, T _ttp Is the desired duration of the torque transfer phase of the transmission shift. The oncoming clutch actuator is commanded to Tq _{on_cltch_cap} The value of (c). The value of T can be measured, and T _ttp The value of (d) may be determined empirically and stored to the controller memory. The torque capacity of the off-going clutch is determined by the following equation:

wherein Tq _{off_cltch_cap} Is about to be separatedClutch torque capacity, tq _{Trn_wo_mod} Is the uncorrected transmission input torque, T is the elapsed time of the torque transfer phase of the current transmission shift, T _ttp Is the desired duration of the torque transfer phase of the transmission shift. The off-going clutch actuator is commanded to Tq _{off_cltch_cap} The value of (c). Oncoming clutch is commanded to Tq _{on_cltch_cap} And the off-going clutch is commanded to Tq _{off_cltch_cap} The value of (c). Method 1000 proceeds to 1013.

At 1013, method 1000 estimates a transmission torque ratio in response to the capacity of the off-going clutch and the capacity of the on-coming clutch. In one example, the transmission torque ratio is determined by the following equation:

wherein RT _actual Is the actual transmission torque ratio, RT _new Is the transmission torque ratio, RT, when the new gear is fully engaged _old Is the transmission torque ratio at full old gear engagement, tq _{on_cltch_cap} Is the capacity of the oncoming clutch, tq _{Trn_wo_mod} Is the transmission input torque. This calculation may be used to define the "no" path at 1006 and 1016 of fig. 10. If the recorded torque ratio is approximately calculated from the ratio of transmission input speed to transmission output speed, the "yes" path at 1006 and 1016 is taken.

The method 1000 may communicate the actual transmission torque ratio to a vehicle system controller, and the vehicle system controller may command the engine and/or the integrated starter/generator to provide the transmission input torque during the torque transfer and inertia phases of the shift, as described at 1010, or by an alternative calculation. For example, the engine and/or integrated starter generator may be commanded to provide a torque equal to Tq _{Trn_min_inst} The transmission input torque. Method 1000 proceeds to exit.

At 1016, method 1000 judges whether or not transmission torque ratio is approximately calculated or estimated by transmission speed ratio. If the transmission is requesting transmission input torque from a vehicle system controller, method 1000 may estimate a transmission torque ratio from a transmission speed ratio. If method 1000 concludes that the transmission torque ratio is estimated by the transmission speed ratio, the answer is yes and method 1000 proceeds to 1018. Otherwise, the answer is no and method 1000 proceeds to 1020.

At 1018, method 1000 determines transmission instantaneous torque. The transmission instantaneous torque may be determined using a known transmission torque ratio. In one example, the transmission torque ratio is estimated by dividing the transmission output speed by the transmission input speed. Thus, the transmission torque ratio of the old gear is the transmission output speed at the old gear divided by the transmission input speed at the old gear. The transmission torque ratio is then used to determine the transmission instantaneous torque. The engine torque and the integrated starter/generator torque may be adjusted to provide transmission transient torque. For example, the engine torque and the integrated starter/generator torque may be adjusted to provide a torque equal to the transmission input maximum instantaneous torque limit as determined by the following equation:

wherein Tq _{Trn_inst_max} Is the transmission input maximum instantaneous torque limit, tq _{Trn_in_newgear} Is the transmission input torque, RT, under the new gear immediately after the oncoming clutch is fully engaged _{gear_new} Is the torque ratio of the transmission when engaging the new gear, RT _{gear_old} Is the torque ratio of the transmission, tq, when engaging the old gear _{Trn_in_oldgear} Is the transmission input torque under the old gear during the current shift, J, immediately before the off-going clutch begins to release _{Trn_in} Is the effective input inertia of the variator, omega _{Trn_out} Is the transmission output shaft angular velocity, and T _{shft_dur} Is the duration of the shift or gear ratio change. Tq _{Trn_in_newgear} Is determined before entering the new gear, andTq _{Trn_in_newgear} is based on the transmission input torque immediately before the shift and the new gear as described by the following equation:

wherein Tq _{Trn_in_newgear} Is the transmission input torque, tq, corresponding to the new transmission gear _{Trn_in_oldgear} Is the transmission input torque, TR, corresponding to the old transmission gear at the start of the transmission shift _{gear_old} Is the ratio of torque in the old gear, and TR _{gear_new} Is the torque ratio of the new gear. Tq _{Trn_in_newgear} The determination is made before the new gear is engaged and before the oncoming clutch is fully engaged. Method 1000 proceeds to 1019.

At 1019, method 1000 controls the oncoming clutch and the offgoing clutch. In one example, the oncoming clutch is adjusted in response to the following equation:

wherein Tq _{on_clth_cap} Is the torque capacity, RT, of the oncoming clutch _reported Is a recorded transmission torque ratio, RT, as determined by dividing the output speed of the transmission by the input speed of the transmission _{gear_new} Is the torque ratio of the transmission when it engages a new gear, and Tq _{Trn_wo_mod} Is the transmission input torque without correction. The offgoing clutch may be adjusted in response to a predetermined clutch torque capacity profile stored in the controller memory or a calculated capacity of the offgoing clutch. Method 1000 proceeds to exit.

At 1020, method 1000 adjusts the recorded transmission torque ratio to that of the transmission when the new gear is fully engaged. For example, if the new gear is the third gear, the recorded transmission torque ratio is adjusted to the transmission torque ratio when the transmission is operating under the new gear (e.g., the new gear is fully engaged). The transmission torque ratio for the new gear may be empirically determined and stored in controller memory. Method 1000 proceeds to 1022.

At 1022, method 1000 estimates the uncorrected transmission input torque. In one example, an uncorrected transmission torque is determined as described at 1010. Method 1000 proceeds to 1024.

At 1024, method 1000 estimates the inertial torque caused by the transmission gear ratio change. In one example, the inertia torque produced by a transmission gear ratio change may be estimated by the following equation:

wherein Tq _{Trn_int} Is an estimate of the transmission inertia torque, RT _{gear_new} Is the torque ratio, RT, of the transmission operating under the new gear _{gear_old} Is the torque ratio of the transmission operating under the old gear, J _{Trn_in} Is the effective input inertia of the variator, omega _{Trn_out} Is the angular velocity of the output shaft of the transmission, and T _{shft_dur} Is the duration of the shift or gear ratio change. Method 1000 proceeds to 1026.

At 1026, method 100 adjusts the wheel torque by subtracting the inertia torque from the engine torque and the integrated starter/generator torque determined from the desired wheel torque. Specifically, method 1000 subtracts the inertia torque from the uncorrected transmission input torque. The engine and integrated starter/generator are commanded to torques produced by subtraction. In this way, the inertia torque may be compensated by reducing the transmission input torque during the inertia phase of the shift. Method 1000 proceeds to exit.

At 1030, method 1000 judges whether or not a downshift is requested. A downshift is a transmission shift from a higher gear (e.g., gear 4) to a lower gear (e.g., gear 3). When the vehicle is decelerating or during hard acceleration, a downshift may be requested when the desired gear is changed from a higher gear to a lower gear. The downshift may be based on a schedule stored in the controller memory. The shift schedule may output a desired transmission gear in response to vehicle speed and accelerator pedal position. The desired gear ratio in the shift schedule may be determined empirically. If method 1000 concludes that a downshift is requested, the answer is yes and method 1000 proceeds to 1032. Otherwise, the answer is no and method 1000 proceeds to 1070.

At 1032, method 100 judges whether or not the inertia phase of the transmission shift is in progress. A power-on transmission gear downshift may consist of two stages. The first phase is an inertia phase, which is the time during a shift when the torque capacity of the off-going clutch is reduced while the on-coming clutch is fully engaged. The reduced torque capacity of the off-going clutch allows the transmission input (e.g., clutch housing) to accelerate to a synchronous rotational speed of the input shaft which transmits torque to the new gear. The synchronizer of the new gear may be engaged such that the input shaft connected to the new gear rotates at a speed that is a function of the transmission output speed and the ratio of the new gear. The inertia phase ends when the transmission input speed (e.g., housing speed) matches the speed of the input shaft connected to the new gear. During the torque transfer phase following the inertia phase, the oncoming clutch begins to engage and the off-going clutch continues to release. In one example, method 1000 may conclude that a shift is in an inertia phase when the oncoming clutch is released before the transmission input speed (e.g., clutch housing speed) matches the input shaft speed of the new gear. If the method 1000 concludes that the shift is in the inertia phase, the answer is yes and the method 1000 proceeds to 1034. Otherwise, the answer is no and method 1000 proceeds to 1060.

At 1034, method 1000 judges whether or not the transmission torque ratio is approximately calculated from the measured transmission input speed and transmission output speed. Method 1000 may conclude that a transmission torque ratio is approximately calculated from a transmission input speed and a transmission output speed during a condition in which a transmission controller controls torque transfer through the transmission. On the other hand, if the vehicle system controller controls torque through the transmission, it may be desirable to determine the transmission torque ratio by the torque capacity of the transmission clutch (e.g., the amount of torque that the transmission clutch may transfer from its input to its output). If method 1000 concludes that the transmission controller adjusts torque flow through the transmission and determines a transmission torque ratio from the transmission input speed and the transmission output speed, the answer is yes and method 1000 proceeds to 1036. Otherwise, the answer is no and method 1000 proceeds to 1050.

At 1036, method 1000 determines a torque ratio of the transmission by dividing the transmission output speed by the transmission input speed. The transmission input speed may be determined by an engine speed sensor and the transmission output speed may be determined by a transmission output speed sensor. Method 1000 proceeds to 1038.

At 1038, method 1000 estimates an inertia torque caused by the transmission gear ratio change. In one example, the inertial torque caused by the transmission gear ratio change may be estimated by the following equation:

wherein Tq _{Trn_int} Is an estimate of the variator inertia torque, RT _{gear_new} Is the torque ratio, RT, of the transmission operating under the new gear _{gear_old} Is the torque ratio of the transmission operating under the old gear, J _{Trn_in} Is the effective input inertia of the variator, ω _{Trn_out} Is the angular velocity of the output shaft of the transmission, and T _{shft_dur} Is the duration of the shift or gear ratio change. Method 1000 proceeds to 1040.

At 1040, method 1000 judges whether inertia torque compensation is desired. Inertia torque compensation may be desired during prescribed vehicle speed and wheel torque demand conditions. If method 1000 concludes that inertia torque compensation is desired, the answer is yes and method 1000 proceeds to 1042. Otherwise, the answer is no and method 1000 proceeds to 1043.

At 1042, method 1000 determines a transmission minimum instantaneous torque limit, which may be referred to as a transmission lower threshold torque. The transmission transient torque may be determined by the following equation:

wherein Tq _{Trn_min_inst} Is the minimum instantaneous torque limit, RT, of the transmission _reported Is the recorded transmission gear ratio, RT _{gear_old} Is the transmission torque ratio at full engagement of the old gear, tq _{Trn_wo_mod} Is uncorrected transmission input torque, J _{Trn_in} Is the effective input inertia of the variator, omega _{Trn_out} Is the transmission output shaft angular velocity, and T _{shft_dur} Is the duration of the shift or gear ratio change. The engine torque and the integrated starter/generator torque are commanded such that the sum of the engine torque and the integrated starter/generator torque is equal to Tq _{Trn_min_inst} To compensate for the inertia torque. In this manner, the transmission input torque is represented by the second term of the equation (e.g.,

) To compensate for the inertia torque. The method 1000 proceeds to 1044.

At 1044, method 1000 determines and commands capacity of the oncoming clutch. In one example, the capacity of the off-going clutch is determined by the following equation:

wherein Tq _{off_clth_cap} Is the torque capacity of the off-going clutch, RT _reported Is the recorded transmission gear ratio, RT _{gear_old} Is the transmission torque ratio at which the old gear is fully engaged, and Tq _{Trn_wo_mod} Is the transmission input torque without correction. The off-going clutch is commanded to Tq _{off_cltch_cap} The value of (c). The method 1000 exits.

At 1043, method 1000 determining a minimum instantaneous transmission torque limit Tq _{Trn_min_inst} This minimum instantaneous torque limit may be referred to as a transmission lower threshold torque. The transmission transient torque may be determined by the following equation:

wherein Tq _{Trn_min_inst} Is the minimum instantaneous torque limit, RT, of the transmission _reported Is the recorded transmission gear ratio, RT _{gear_old} Is the transmission torque ratio at full old gear engagement, and Tq _{Trn_wo_mod} Is the transmission input torque without correction. The engine torque and the integrated starter/generator torque are commanded such that the sum of the engine torque and the integrated starter/generator torque equals Tq _{Trn_min_inst} And no inertia torque compensation is provided. Method 1000 proceeds to 1045.

At 1045, method 1000 determines and commands a capacity of the clutch to be disengaged. In one example, the capacity of the off-going clutch is determined by the following equation:

wherein Tq _{off_clth_cap} Is the torque capacity, RT, of the offgoing clutch _reported Is the recorded transmission gear ratio, RT _{gear_old} Is the transmission torque ratio at full engagement of the old gear, J _{Trn_in} Is the effective input inertia of the variator, omega _{Trn_out} Is the transmission output shaft angular velocity, and T _{shft_dur} Is the duration of the shift or gear ratio change, and Tq _{Trn_wo_mod} Is the transmission input torque without correction. The off-going clutch is commanded to Tq _{off_cltch_cap} The value of (c). Method 1000 proceeds to exit.

At 1050, method 1000 adjusts the recorded transmission torque ratio to that of the transmission when the new gear is fully engaged. For example, if the new gear is the third gear, the recorded transmission torque ratio is adjusted to the transmission torque ratio when the transmission is operating under the new gear (e.g., the new gear is fully engaged). The transmission torque ratio for the new gear may be empirically determined and stored in controller memory. The method 1000 proceeds to 1052.

At 1052, method 1000 estimates the uncorrected transmission input torque. In one example, the uncorrected transmission torque is determined as described at 1010. Method 1000 proceeds to 1054.

At 1054, method 1000 estimates the inertia torque caused by the transmission gear ratio change. In one example, the inertia torque caused by the transmission gear ratio change may be estimated by the following equation:

wherein Tq _{Trn_int} Is an estimate of the transmission inertia torque, RT _{gear_new} Is the torque ratio, RT, of the transmission operating under the new gear _{gear_old} Is the torque ratio of the transmission operating under the old gear, J _{Trn_in} Is the effective input inertia of the variator, ω _{Trn_out} Is the transmission output shaft angular velocity, and T _{shft_dur} Is the duration of the shift or gear ratio change. Method 1000 proceeds to 1056.

At 1056, method 1000 determines and commands an oncoming clutch torque capacity and an oncoming clutch capacity. In one example, the capacity of the off-going clutch may be determined as described at 1045. The torque capacity of the oncoming clutch may be determined as described at 1019. Method 1000 commands clutch torque capacity and proceeds to 1058.

At 1058, the method 1000 optionally adjusts the wheel torque by increasing an inertia torque from the engine torque and the integrated starter/generator torque determined from the desired wheel torque. Specifically, method 1000 subtracts the inertia torque from the uncorrected transmission input torque. The engine and integrated starter/generator are commanded to torques produced by subtraction. In this way, the inertia torque may be compensated by reducing the transmission input torque during the inertia phase of the shift. Method 1000 proceeds to exit.

At 1060, method 1000 judges whether or not the transmission torque ratio is approximately calculated or estimated from the transmission speed ratio. If the transmission is requesting transmission input torque from a vehicle system controller, method 1000 may estimate a transmission torque ratio from the transmission speed ratio. If method 1000 concludes that the transmission torque ratio is estimated from the transmission speed ratio, the answer is yes and method 1000 proceeds to 1062. Otherwise, the answer is no and method 1000 proceeds to 1063.

At 1062, method 1000 estimates transmission input torque. As previously described, transmission input torque may be estimated as Tq in response to accelerator pedal position _{Trn_wo_mod} The value of (c). The method 1000 proceeds to 1064.

At 1064, method 1000 determines a torque ratio of the transmission by dividing the transmission output speed by the transmission input speed. The transmission input speed may be determined by an engine speed sensor and the transmission output speed may be determined by a transmission output speed sensor. The method 1000 proceeds to 1066.

At 1066, the method 1000 determines and commands the clutch to be disengaged. The capacity of the off-going clutch may be determined by the following equation:

wherein Tq _{on_cltch_cap} Is the oncoming clutch torque capacity, tq _{Trn_wo_mod} Is the uncorrected transmission input torque, T is the elapsed time of the torque transfer phase of the current transmission shift, T _ttp Is the desired duration of the torque transfer phase of the transmission shift. Method 1000 proceeds to 1068.

At 1068, method 1000 determines a transmission minimum instantaneous torque limit Tq _{Trn_min_inst} Minimum instantaneous of the transmissionThe torque limit may be referred to as a transmission lower threshold torque. The transmission transient torque may be determined by the following equation:

wherein Tq _{Trn_min_inst} Is the minimum instantaneous torque limit, RT, of the transmission _{gear_old} Is the transmission torque ratio of the initial gear, RT _{gear_new} Is the transmission torque ratio at full engagement of the new gear, and Tq _{Trn_wo_mod} Is the transmission input torque without correction. The engine torque and the integrated starter/generator torque are commanded such that the sum of the engine torque and the integrated starter/generator torque equals Tq _{Trn_min_inst} The value of (c). Method 1000 proceeds to exit.

At 1063, method 1000 estimates transmission input torque. As previously described, transmission input torque may be estimated as Tq in response to accelerator pedal position _{Trn_wo_mod} The value of (c). The method 1000 proceeds to 1065.

At 1065, method 1000 determines and commands a capacity of the oncoming clutch and a capacity of the offgoing clutch. The capacity of the oncoming clutch may be determined by the following equation:

wherein Tq _{on_cltch_cap} Is the torque capacity of the oncoming clutch, tq _{Trn_wo_mod} Is the uncorrected transmission input torque, T is the elapsed time of the torque transfer phase of the current transmission shift, T _ttp Is the desired duration of the torque transfer phase of the transmission shift. Oncoming clutch actuator is commanded to Tq _{on_cltch_cap} The value of (c). The value of T can be measured, and T _ttp May be empirically determined and stored to the controller memory. The torque capacity of the off-going clutch is determined by the following equation:

wherein Tq _{off_cltch_cap} Is the off-going clutch torque capacity, tq _{Trn_wo_mod} Is the uncorrected transmission input torque, T is the elapsed time of the torque transfer phase of the current transmission shift, T _ttp Is the desired duration of the torque transfer phase of the transmission shift. The off-going clutch actuator is commanded to Tq _{off_cltch_cap} The value of (c). The oncoming clutch is commanded to Tq _{on_cltch_cap} And the off-going clutch is commanded to Tq _{off_cltch_cap} The value of (c). Method 1000 proceeds to 1067.

At 1067, method 1000 estimates a transmission torque ratio in response to the capacity of the offgoing clutch and the capacity of the oncoming clutch. In one example, the transmission torque ratio is determined by the following equation:

wherein RT is _actual Is the actual transmission torque ratio, RT _actual May alternatively be referred to as a recorded transmission torque ratio, RT _new Is the transmission torque ratio at full engagement of the new gear, RT _old Is the transmission torque ratio at full engagement of the old gear, tq _{on_cltch_cap} Is the capacity of the oncoming clutch, tq _{off_cltch_cap} Is the capacity of the offgoing clutch. The method 1000 may communicate the actual transmission torque ratio to a vehicle system controller, and the vehicle system controller may command the engine and/or the integrated starter/generator to provide the transmission input torque during the torque transfer and inertia phases of the shift. For example, the engine and/or integrated starter/generator may be commanded to provide a torque equal to Tq _{Trn_min_inst} The transmission input torque. Method 1000 proceeds to exit.

At 1070, method 1000 judges whether or not engine start is requested. Engine start may be requested by the driver or an automated driver. In one example, method 1000 evaluates the state of a controller input to determine whether an engine start is requested. If method 1000 concludes that an engine start is requested, the answer is yes and method 1000 proceeds to 1072. Otherwise, the answer is no and method 1000 proceeds to 1071.

At 1071, if the engine is started, the method 1000 maintains the torque ratio of the current transmission. Additionally, in some conditions, the transmission clutch may be maintained in a disengaged state if the engine is stopped. Method 1000 proceeds to exit.

At 1072, method 1000 judges whether or not the torque capacities of both transmission clutches are greater than zero and both clutches are transmitting torque. If the force applied to engage the clutches is not zero, then the method 1000 may conclude that the torque capacities of both clutches are not zero. If method 1000 concludes that the torque capacities of the two transmission clutches are not zero, the answer is yes and method 1000 proceeds to 1074. Otherwise, the answer is no and method 1000 proceeds to 1073.

At 1073, method 1000 adjusts the transmission torque ratio to the desired transmission torque ratio with the gears fully engaged. Method 1000 proceeds to exit.

At 1074, method 1000 judges whether or not only the clutch for the higher gear is slipping. For example, if the first clutch transmits engine torque to the first gear, and the second clutch transmits engine torque to the second gear, and only the second clutch is slipping, the answer is yes. If method 1000 concludes that only the clutch for the higher gear is slipping, the answer is yes and method 1000 proceeds to 1076. Otherwise, the answer is no and method 1000 proceeds to 1075.

At 1075, method 1000 adjusts the transmission torque ratio to a weighted average of the transmission torque ratio when the first gear (e.g., the gear supplied torque by the first transmission clutch) is fully engaged and the transmission torque ratio when the second gear (e.g., the gear supplied torque by the second transmission clutch) is fully engaged. Method 1000 proceeds to exit.

At 1076, method 1000 adjusts the transmission torque ratio to that of the higher gear. For example, if the first clutch transmits engine torque to gear 1 and the second clutch transmits engine torque to gear 2, the transmission torque ratio is set to that of gear 2. Method 1000 proceeds to exit.

In this way, transmission torque ratios may be recorded in response to transmission input speed and transmission output speed. Further, transmission torque ratios may be recorded in response to torque capacities of transmission clutches without using transmission input and output speeds.

It should be noted that the exemplary control and estimation routines included herein can be used with various engine and/or vehicle system configurations. The control methods and programs disclosed herein may be stored as executable instructions in non-transitory memory and executed by a control system, including a controller, in conjunction with various sensors, actuators, and other engine hardware.

Furthermore, part of the method may be a physical action taken in the real world to change the state of the device. The specific routines described herein may represent one or more of any number of processing strategies such as event-driven, interrupt-driven, multi-tasking, multi-threading, and the like. As such, various acts, operations, and/or functions illustrated may be performed in the sequence illustrated, in parallel, or in some cases omitted. Likewise, the timing of the processes is not necessarily required to achieve the features and advantages of the example embodiments described herein, but is provided for ease of illustration and description. One or more of the illustrated acts, operations, and/or functions may be repeatedly performed depending on the particular strategy being used. Further, the described acts, operations, and/or functions may graphically represent code to be programmed into the non-transitory memory of the computer readable storage medium in the engine control system, wherein the described acts are performed by executing instructions in the system comprising the various engine hardware components in combination with the electronic controller. One or more of the method steps described herein may be omitted, if desired.

It will be appreciated that the configurations and routines disclosed herein are exemplary in nature, and that these specific embodiments are not to be considered in a limiting sense, because numerous variations are possible. For example, the above-described techniques may be applied to V-6, I-4, I-6, V-12, opposed 4, and other engine types. The subject matter of the present disclosure includes all novel and nonobvious combinations and subcombinations of the various systems and configurations, and other features, functions, and/or properties disclosed herein.

The following claims particularly point out certain combinations and subcombinations regarded as novel and nonobvious. These claims may refer to "an" element or "a first" element or the equivalent thereof. Such claims should be understood to include incorporation of one or more such elements, neither requiring nor excluding two or more such elements. Other combinations and subcombinations of the disclosed features, functions, elements, and/or properties may be claimed through amendment of the present claims or through presentation of new claims in this or a related application. Such claims, whether broader, narrower, equal, or different in scope to the original claims, also are regarded as included within the subject matter of the present disclosure.

Claims

1. A method of operating a powertrain comprising:

reducing, by the controller, the transmission input torque during a power-on upshift to a transmission transient upper threshold torque responsive to the recorded transmission torque ratio, the transmission torque ratio under the new gear, the transmission inertia, and the duration of the desired transmission upshift;

wherein the recorded transmission torque ratio is determined from a transmission input speed and a transmission output speed; or

Wherein the recorded transmission torque ratio is determined by a clutch capacity of an oncoming clutch and a torque ratio of the transmission when the transmission engages the new gear;

the new gear is the gear that is engaged immediately after the power-on upshift is completed.

2. The method of claim 1, further comprising:

reducing the transmission input torque to less than a transmission hardware upper torque limit threshold.

3. The method of claim 1, wherein engine torque is adjusted to the value of the transmission instantaneous upper threshold torque.

4. The method of claim 1, wherein reducing the transmission input torque comprises reducing torque of a rear wheel drive electric machine or a motor disposed directly downstream of a transmission output or reducing torque of an electric machine having a separate drive shaft.

5. The method of claim 1, wherein reducing the transmission input torque comprises reducing an amount of regenerative torque of a rear wheel drive motor when the rear wheel drive is providing power to the power storage device.

6. The method of claim 1, further comprising commanding, by the controller, a torque capacity of an oncoming clutch in response to a torque ratio of the transmission at which the transmission engages the new gear and in response to the recorded torque ratio of the transmission.

7. The method of claim 6, further comprising commanding a torque capacity of the on-coming clutch in response to the estimated transmission input torque and the estimated equivalent transmission input torque.

8. The method of claim 7, wherein the estimated equivalent transmission torque is responsive to a torque of a rear wheel drive electric machine or a torque of a motor disposed directly downstream of the transmission or a torque of an electric machine having a separate drive shaft.

9. The method of claim 8, wherein the estimated transmission input torque is responsive to transmission clutch slip.

10. The method of claim 6, wherein the transmission input torque is reduced by reducing torque of a rear wheel drive motor when the rear wheel drive provides positive torque to the driveline.

11. The method of claim 6, wherein reducing the transmission input torque comprises providing regenerative braking torque by a rear wheel drive motor.

12. The method of claim 6, wherein reducing the transmission input torque comprises reducing engine torque and integrated starter/generator torque without adjusting a regenerative braking torque of a rear wheel drive motor when the rear wheel drive motor is providing regenerative braking torque.

13. The method of claim 1, further comprising adjusting, by the controller, a transmission instantaneous lower limit torque threshold in response to the recorded transmission torque ratio in response to a torque capacity of the offgoing clutch and an estimated transmission input torque, a transmission torque ratio in old gear, and an uncorrected transmission input torque;

wherein the old gear is a split gear and the uncorrected transmission input torque is represented by the following equation:

wherein Tq _{Trn_wo_mod} Is the uncorrected transmission input torque, tq _{dd_whl} Is determined by the position of an accelerator pedalSetting the determined driver demanded wheel torque, tq _Rdu Is the output torque of the motor of the rear wheel drive, gr _Rdu Is the rear wheel drive torque ratio, gr _Trn Is the currently engaged transmission torque ratio, and Tq _Isg Is the torque output by the integrated starter/generator.

14. A method of operating a powertrain comprising:

commanding, by the controller, a torque capacity of an oncoming clutch in response to a torque ratio of the transmission at which the transmission engages the new gear and in response to the recorded torque ratio of the transmission;

15. A method of operating a powertrain comprising:

adjusting, by the controller, a transmission transient lower limit torque threshold in response to a recorded transmission torque ratio in response to a torque capacity of the off-going clutch and the estimated transmission input torque, a transmission torque ratio in the old gear, and an uncorrected transmission input torque; and

adjusting, by the controller, a torque of an engine in response to the transmission transient lower limit torque threshold;

wherein Tq _{Trn_wo_mod} Is the uncorrected transmission input torque, tq _{dd_whl} Is the driver's required wheel torque, tq, determined by the accelerator pedal position _Rdu Is the output torque of the motor of the rear wheel drive, gr _Rdu Is the rear wheel drive torque ratio, gr _Trn Is the currently engaged transmission torque ratio, and Tq _Isg Is the torque output by the integrated starter/generator.